How to upgrade Laravel from 5.7 to 5.8

I have been googling and reading on this for several days.
I am unable to update my Laravel project from 5.7 to 5.8, due to dependencies. When I update the dependency package version values in composer.json and try to perform a laravel update, it ignores my updates, and actually reverts them back to the original values.

Composer.json

{
"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": ["framework", "laravel"],
"license": "MIT",
"type": "project",
"require": {
    "php": "^7.1.3",
    "anhskohbo/no-captcha": "^3.0",
    "chriskonnertz/open-graph": "^1.0",
    "cmgmyr/messenger": "^2.16",
    "cviebrock/eloquent-sluggable": "^4.6",
    "doctrine/dbal": "^2.8",
    "egeloen/http-adapter": "^1.0",
    "eilander/gateway": "^5.6",
    "exodusanto/administrator": " 5.7.*",
    "fideloper/proxy": "^4.0",
    "fzaninotto/faker": "^1.8",
    "geocoder-php/bing-maps-provider": "^4.0",
    "geocoder-php/chain-provider": "^4.0",
    "geocoder-php/google-maps-provider": "^4.2",
    "geoip2/geoip2": "^2.9",
    "hemp/presenter": "^1.0",
    "hieu-le/active": "^3.5",
    "htmlmin/htmlmin": "^5.8",
    "intervention/image": "^2.4",
    "laravel/framework": "5.7.*",
    "laravel/passport": "^7.0",
    "laravel/socialite": "^4.1",
    "laravel/tinker": "^1.0",
    "laravelcollective/html": "^5.7",
    "league/period": "4.1.0",
    "maatwebsite/excel": "^3.1",
    "morrislaptop/laravel-queue-clear": "^1.1",
    "php-http/guzzle6-adapter": "^1.1",
    "php-http/message": "^1.7",
    "phpoffice/phpspreadsheet": "^1.5",
    "pragmarx/firewall": "^2.2",
    "predis/predis": "^1.1",
    "prettus/l5-repository": "^2.6",
    "prettus/laravel-validation": "^1.1",
    "ryanwinchester/hubspot-php": "~1.0",
    "sammyk/laravel-facebook-sdk": "^3.5",
    "santigarcor/laratrust": "^5.0",
    "spatie/laravel-newsletter": "^4.2",
    "toin0u/geocoder-laravel": "^4.0",
    "torann/geoip": "^1.0",
    "venturecraft/revisionable": "^1.28",
    "watson/sitemap": "^2.0",
    "yajra/laravel-datatables-oracle": "^8.9"
},
"require-dev": {
    "beyondcode/laravel-dump-server": "^1.0",
    "filp/whoops": "^2.0",
    "mockery/mockery": "^1.0",
    "nunomaduro/collision": "^2.0",
    "phpunit/phpunit": "^7.0"
},
"autoload": {
    "classmap": [
        "database/seeds",
        "database/factories"
    ],
    "psr-4": {
        "App\": "app/"
    }
},
"autoload-dev": {
    "psr-4": {
        "Tests\": "tests/"
    }
},
"extra": {
    "laravel": {
        "dont-discover": [
        ]
    }
},
"scripts": {
    "post-root-package-install": [
        "@php -r "file_exists('.env') || copy('.env.example', '.env');""
    ],
    "post-create-project-cmd": [
        "@php artisan key:generate"
    ],
    "post-autoload-dump": [
        "Illuminate\Foundation\ComposerScripts::postAutoloadDump",
        "@php artisan package:discover"
    ]
},
"config": {
    "preferred-install": "dist",
    "sort-packages": true,
    "optimize-autoloader": true
},
"minimum-stability": "dev",
"prefer-stable": true

}

Steps I take:

1) Edit my composer.json file, changing: “laravel/framework”: “5.7.“
to: “laravel/framework”: “5.8.“

2) Run composer update

Output:

Loading composer repositories with package information
Updating dependencies (including require-dev)
Nothing to install or update
Package egeloen/http-adapter is abandoned, you should avoid using it. Use php-http/httplug instead.
Generating optimized autoload files
Carbon 1 is deprecated, see how to migrate to Carbon 2.
https://carbon.nesbot.com/docs/#api-carbon-2
    You can run ".vendorbinupgrade-carbon" to get help in updating carbon and other frameworks and libraries that depend on it.
> IlluminateFoundationComposerScripts::postAutoloadDump
> @php artisan package:discover
Discovered Package: anhskohbo/no-captcha
Discovered Package: beyondcode/laravel-dump-server
Discovered Package: chriskonnertz/open-graph
Discovered Package: cmgmyr/messenger
Discovered Package: cviebrock/eloquent-sluggable
Discovered Package: exodusanto/administrator
Discovered Package: fideloper/proxy
Discovered Package: hemp/presenter
Discovered Package: hieu-le/active
Discovered Package: htmlmin/htmlmin
Discovered Package: intervention/image
Discovered Package: laravel/nexmo-notification-channel
Discovered Package: laravel/passport
Discovered Package: laravel/slack-notification-channel
Discovered Package: laravel/socialite
Discovered Package: laravel/tinker
Discovered Package: laravelcollective/html
Discovered Package: maatwebsite/excel
Discovered Package: morrislaptop/laravel-queue-clear
Discovered Package: nesbot/carbon
Discovered Package: nunomaduro/collision
Discovered Package: pragmarx/firewall
Discovered Package: prettus/l5-repository
Discovered Package: sammyk/laravel-facebook-sdk
Discovered Package: santigarcor/laratrust
Discovered Package: spatie/laravel-newsletter
Discovered Package: toin0u/geocoder-laravel
Discovered Package: torann/geoip
Discovered Package: watson/sitemap
Discovered Package: yajra/laravel-datatables-oracle
Package manifest generated successfully.

Result:

composer.json file has been reset to show : “laravel/framework”: “5.7.*”

Things I’ve tried:
1) Deleting the composer.lock file prior to attempting this.
2) Performing a php artisan cache:clear prior to my updates.

There has to be someone out there who has experienced these issues that can help me out.