ci: install .NET 8 SDK in CI and builds

Author: mjcheetham

.github/workflows/continuous-integration.yml

@@ -21,7 +21,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v3.2.0
       with:
-        dotnet-version: 6.0.201
+        dotnet-version: 8.0.x
 
     - name: Install dependencies
       run: dotnet restore
@@ -61,7 +61,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v3.2.0
       with:
-        dotnet-version: 6.0.201
+        dotnet-version: 8.0.x
 
     - name: Install dependencies
       run: dotnet restore
@@ -102,7 +102,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v3.2.0
       with:
-        dotnet-version: 6.0.201
+        dotnet-version: 8.0.x
 
     - name: Install dependencies
       run: dotnet restore

.github/workflows/release.yml

@@ -20,7 +20,7 @@ jobs:
     - name: Set up dotnet
       uses: actions/setup-dotnet@v3.2.0
       with:
-        dotnet-version: 6.0.201
+        dotnet-version: 8.0.x
 
     - name: Install dependencies
       run: dotnet restore
@@ -144,7 +144,7 @@ jobs:
     - name: Set up dotnet
       uses: actions/setup-dotnet@v3.2.0
       with:
-        dotnet-version: 6.0.201
+        dotnet-version: 8.0.x
 
     - name: Download signed payload
       uses: actions/download-artifact@v3
@@ -252,7 +252,7 @@ jobs:
     - name: Set up dotnet
       uses: actions/setup-dotnet@v3.2.0
       with:
-        dotnet-version: 6.0.201
+        dotnet-version: 8.0.x
 
     - name: Install dependencies
       run: dotnet restore
@@ -353,7 +353,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v3.2.0
       with:
-        dotnet-version: 6.0.201
+        dotnet-version: 8.0.x
 
     - name: Install dependencies
       run: dotnet restore
@@ -440,7 +440,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v3.2.0
       with:
-        dotnet-version: 6.0.201
+        dotnet-version: 8.0.x
 
     - name: Build .NET tool
       run: |
@@ -533,7 +533,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v3.2.0
       with:
-        dotnet-version: 6.0.201
+        dotnet-version: 8.0.x
 
     - name: Package tool
       run: |
@@ -710,7 +710,7 @@ jobs:
       - name: Set up dotnet
         uses: actions/setup-dotnet@v3.2.0
         with:
-          dotnet-version: 6.0.201
+          dotnet-version: 8.0.x
 
       - name: Download artifacts
         uses: actions/download-artifact@v3