pin dotnet sdk version used in github actions (#1508)

.github/workflows/artifacts.yml

@@ -49,7 +49,7 @@ jobs:
       - name: Setup .NET Core
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: 7.0.x
+          dotnet-version: 7.0.306
 
       - name: Setup Node.js
         uses: actions/setup-node@v3
@@ -175,7 +175,7 @@ jobs:
       - name: Setup .NET Core
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: 7.0.x
+          dotnet-version: 7.0.306
 
       - name: Setup Node.js
         uses: actions/setup-node@v3

.github/workflows/pr.yml

@@ -11,7 +11,7 @@ jobs:
       - name: Setup .NET Core
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: 7.0.x
+          dotnet-version: 7.0.306
 
       - name: Setup Rust
         uses: actions-rs/toolchain@v1
@@ -46,7 +46,7 @@ jobs:
       - name: Setup .NET Core
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: 7.0.x
+          dotnet-version: 7.0.306
 
       - name: Clean
         run: dotnet clean --configuration Release && dotnet nuget locals all --clear
@@ -74,7 +74,7 @@ jobs:
       - name: Setup .NET Core
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: 7.0.x
+          dotnet-version: 7.0.306
 
       - name: Clean
         run: dotnet clean --configuration Release && dotnet nuget locals all --clear