Update .NET version in workflow to include 9.0.x, drop 3.1

Author: RohrerF

.github/workflows/dotnet.yml

@@ -15,9 +15,9 @@ jobs:
       uses: actions/setup-dotnet@v1
       with:
         dotnet-version: | 
-          3.1.x
           6.0.x
           8.0.x
+          9.0.x
     - name: Restore dependencies
       run: dotnet restore
     - name: Build
@@ -31,10 +31,10 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: |
-            3.1.x
+          dotnet-version: | 
             6.0.x
             8.0.x
+            9.0.x
       - name: Restore dependencies
         run: dotnet restore
       - name: Build
@@ -48,10 +48,10 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: |
-            3.1.x
+          dotnet-version: | 
             6.0.x
             8.0.x
+            9.0.x
       - name: Restore dependencies
         run: dotnet restore
       - name: Build
@@ -65,10 +65,10 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: |
-            3.1.x
+          dotnet-version: | 
             6.0.x
             8.0.x
+            9.0.x
       - name: Restore dependencies
         run: dotnet restore
       - name: Build
@@ -82,10 +82,10 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: |
-            3.1.x
+          dotnet-version: | 
             6.0.x
             8.0.x
+            9.0.x
       - name: Restore dependencies
         run: dotnet restore
       - name: Build
@@ -99,10 +99,10 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: |
-            3.1.x
+          dotnet-version: | 
             6.0.x
             8.0.x
+            9.0.x
       - name: Restore dependencies
         run: dotnet restore
       - name: Build
@@ -114,10 +114,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Setup .NET
-        uses: actions/setup-dotnet@v4
+        uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: |
-            3.1.x
+          dotnet-version: | 
             6.0.x
             8.0.x
             9.0.x
@@ -134,10 +133,10 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: |
-            3.1.x
+          dotnet-version: | 
             6.0.x
             8.0.x
+            9.0.x
       - name: Restore dependencies
         run: dotnet restore
       - name: Build