Update actions/cache action to v4 #86

	name: Build and Test
	on:
	push:
	branches:
	- master
	pull_request:
	branches:
	- master
	schedule:
	- cron: '0 0 * * 6' # every Saturday
	workflow_dispatch:

	jobs:
	test:
	runs-on: ${{ matrix.image }}
	strategy:
	fail-fast: false
	matrix:
	image: [macos-12, ubuntu-22.04, windows-2022]
	env:
	DOTNET_NOLOGO: 1
	DOTNET_CLI_TELEMETRY_OPTOUT: 1
	NUGET_PACKAGES: ${{ github.workspace }}/.github/nuget-packages
	steps:
	- uses: actions/checkout@v2

	# Backend
	- name: Set up .NET SDK
	uses: actions/setup-dotnet@v4
	with:
	dotnet-version: '8.0.x'
	- name: NuGet Cache
	uses: actions/cache@v4
	with:
	path: ${{ env.NUGET_PACKAGES }}
	key: ${{ runner.os }}.nuget.${{ hashFiles('*/.fsproj') }}
	- name: Backend Build
	run: dotnet build --configuration Release
	- name: Backend Publish
	run: dotnet publish --configuration Release

Provide feedback