[ci-skip] Switch ci (DSharpPlus#1221)

* Remove old AppVeyor files to pave way for GH Actions

* Updated .gitignore

* Tested and confirmed that CI works as intended

* Update README.md

* ✨ Grammar ✨

* Update last AppVeyor number and formatting

* Update last AppVeyor build id

* Update last AppVeyor build id

* Update last AppVeyor build id

.github/workflows/publish_nightly.yml

@@ -0,0 +1,24 @@
+name: "Publish Nightly"
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  publish_nightly:
+    runs-on: "ubuntu-latest"
+    if: "!contains(toJSON(github.event.commits.*.message), '[ci-skip]')"
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v2"
+
+      - name: "Setup .NET"
+        uses: "actions/setup-dotnet@v1"
+        with:
+          dotnet-version: "6.0.x"
+
+      - name: "Build Nightly Nuget Packages"
+        run: "mkdir build && dotnet pack -p:SymbolPackageFormat=snupkg --include-symbols --include-source -o build -p:VersionSuffix='nightly' -p:BuildNumber=0$(( 1091 + ${{ github.run_number }} ))" # We add 1091 since it's the last build number AppVeyor used.
+
+      - name: "Publish Nightly Nuget Packages"
+        run: "dotnet nuget push \"build/*\" -k ${{ secrets.NUGET_ORG_API_KEY }} -s https://api.nuget.org/v3/index.json" # If the package version does not comply with SemVer, it will be set as a pre-release version automatically.

.github/workflows/publish_release.yml

@@ -0,0 +1,33 @@
+name: "Publish Release"
+on:
+  release:
+    types: ["published"]
+
+jobs:
+  publish_release:
+    runs-on: "ubuntu-latest"
+    if: "!contains(toJSON(github.event.commits.*.message), '[ci-skip]')"
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v2"
+
+      - name: "Setup .NET"
+        uses: "actions/setup-dotnet@v1"
+        with:
+          dotnet-version: "6.0.x"
+
+      - name: "Build Nuget Packages"
+        run: "mkdir build && dotnet pack -p:SymbolPackageFormat=snupkg --include-symbols -c Release -o build"
+
+      - name: "Publish Nuget Packages"
+        run: "dotnet nuget push \"build/*\" -k ${{ secrets.NUGET_ORG_API_KEY }} -s https://api.nuget.org/v3/index.json"
+
+      - name: "Upload Nuget Packages To Github Release"
+        uses: "ncipollo/release-action@v1"
+        with:
+          allowUpdates: true
+          artifactErrorsFailBuild: true
+          artifacts: "build/*"
+          token: ${{ secrets.GITHUB_TOKEN }}
+          omitBodyDuringUpdate: true # We don't want to update the body of the release.
+          omitNameDuringUpdate: true # We don't want to update the name of the release.

.github/workflows/test_pr.yml

@@ -0,0 +1,20 @@
+name: "Test PR"
+on:
+  pull_request:
+
+jobs:
+  build_pr:
+    runs-on: "ubuntu-latest"
+    if: "!contains(toJSON(github.event.commits.*.message), '[ci-skip]')"
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v2"
+
+      - name: "Setup .NET"
+        uses: "actions/setup-dotnet@v1"
+        with:
+          dotnet-version: "6.0.x"
+
+      - name: "Build PR"
+        run: "dotnet build --nologo"
+      # TODO: Complete DSharpPlus.Test package. Utilizing Github secrets, we can run the bot and have it execute tests on the PR to ensure there aren't any breaking changes.