specify exact .NET version for actions

Author: albho

.github/workflows/dotnet.yml

@@ -38,18 +38,18 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, macos-13, windows-latest]
-        dotnet-version: [2.1.x, 3.0.x, 3.1.x, 5.0.x, 6.0.x, 8.0.x]
+        dotnet-version: [2.1.818, 3.0.103, 3.1.426, 5.0.408, 6.0.x, 8.0.x]
         include:
-          - dotnet-version: 2.1.x
+          - dotnet-version: 2.1.818
             binding-framework: netstandard2.0
             test-framework: netcoreapp2.1
-          - dotnet-version: 3.0.x
+          - dotnet-version: 3.0.103
             binding-framework: netcoreapp3.0
             test-framework: netcoreapp3.0
-          - dotnet-version: 3.1.x
+          - dotnet-version: 3.1.426
             binding-framework: netcoreapp3.0
             test-framework: netcoreapp3.1
-          - dotnet-version: 5.0.x
+          - dotnet-version: 5.0.408
             binding-framework: netcoreapp3.0
             test-framework: net5.0
           - dotnet-version: 6.0.x
@@ -60,21 +60,21 @@ jobs:
             test-framework: net8.0
         exclude:
           - os: ubuntu-latest
-            dotnet-version: 2.1.x
+            dotnet-version: 2.1.818
           - os: ubuntu-latest
-            dotnet-version: 3.0.x
+            dotnet-version: 3.0.103
           - os: ubuntu-latest
-            dotnet-version: 3.1.x
+            dotnet-version: 3.1.426
           - os: ubuntu-latest
-            dotnet-version: 5.0.x
+            dotnet-version: 5.0.408
           - os: macos-latest
-            dotnet-version: 2.1.x
+            dotnet-version: 2.1.818
           - os: macos-latest
-            dotnet-version: 3.0.x
+            dotnet-version: 3.0.103
           - os: macos-latest
-            dotnet-version: 3.1.x
+            dotnet-version: 3.1.426
           - os: macos-latest
-            dotnet-version: 5.0.x
+            dotnet-version: 5.0.408
           - os: macos-latest
             dotnet-version: 6.0.x
           - os: macos-13