Update pull-requests.yml

Author: dsyme

.github/workflows/pull-requests.yml

@@ -12,7 +12,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest]
-        dotnet: [3.1.302, 5.0.100]
+        dotnet: [3.1.302]
     runs-on: ${{ matrix.os }}
 
     steps: