[BREAKING CHANGE]: Removes the .NET 5.0 support (#2806)

.devcontainer/Dockerfile

@@ -1,11 +1,10 @@
 # See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.234.0/containers/dotnet/.devcontainer/base.Dockerfile
 
-# [Choice] .NET version: 6.0, 5.0, 6.0-bullseye, 5.0-bullseye, 6.0-focal, 5.0-focal
+# [Choice] .NET version: 6.0, 6.0-bullseye, 6.0-focal
 ARG VARIANT="6.0-bullseye"
 FROM mcr.microsoft.com/vscode/devcontainers/dotnet
 
-# "install" the dotnet 5.0 & 6.0 runtime for tests
-COPY --from=mcr.microsoft.com/dotnet/sdk:5.0 /usr/share/dotnet/shared /usr/share/dotnet/shared
+# "install" the dotnet 6.0 runtime for tests
 COPY --from=mcr.microsoft.com/dotnet/sdk:6.0 /usr/share/dotnet/shared /usr/share/dotnet/shared
 
 # # Add mkdocs for doc generation

.devcontainer/devcontainer.json

@@ -5,7 +5,7 @@
   "build": {
     "dockerfile": "Dockerfile",
     "args": {
-      // Update 'VARIANT' to pick a .NET Core version: 5.0, 6.0
+      // Update 'VARIANT' to pick a .NET Core version: 6.0
       // Append -bullseye or -focal to pin to an OS version.
       "VARIANT": "latest"
     }

.github/workflows/netcore.yml

@@ -19,10 +19,6 @@ jobs:
 
     steps:
     - uses: actions/checkout@v1
-    - name: Setup .NET 5
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: 5.0.*
     - name: Setup .NET 6
       uses: actions/setup-dotnet@v1
       with:

.github/workflows/publish.yml

@@ -13,10 +13,6 @@ jobs:
     steps:
     - uses: actions/checkout@v1
 
-    - name: Setup .NET 5
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: 5.0.*
     - name: Setup .NET 6
       uses: actions/setup-dotnet@v1
       with: