(build) use DOTNET_ROLL_FORWARD_ON_NO_CANDIDATE_FX

Author: arturcic

.github/workflows/docs.yml

@@ -8,6 +8,9 @@ on:
   pull_request:
     paths:
     - 'docs/**'
+env:
+  DOTNET_ROLL_FORWARD_ON_NO_CANDIDATE_FX: 2
+
 jobs:
   prepare:
     name: Prepare Build
@@ -71,16 +74,6 @@ jobs:
       with:
         path: tools
         key: tools-${{ runner.os }}-${{ hashFiles('./build/**') }}
-    -
-      name: Install .NET SDK 2.1.x
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '2.1.x'
-    -
-      name: Install .NET SDK 5.0.x
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '5.0.x'
     -
       name: Install .NET SDK 6.0.x
       uses: actions/setup-dotnet@v1
@@ -131,16 +124,6 @@ jobs:
       with:
         path: tools
         key: tools-${{ runner.os }}-${{ hashFiles('./build/**') }}
-    -
-      name: Install .NET SDK 2.1.x
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '2.1.x'
-    -
-      name: Install .NET SDK 5.0.x
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '5.0.x'
     -
       name: Install .NET SDK 6.0.x
       uses: actions/setup-dotnet@v1