fix: pipeline

.github/workflows/ci.yml

@@ -20,6 +20,9 @@ env:
   IMAGE: git.greboh.dev/greboh/hearth-api
   DOTNET_NOLOGO: true
   DOTNET_CLI_TELEMETRY_OPTOUT: true
+  # Inside the runner's shared tool cache, so the SDK and packages carry over between runs.
+  DOTNET_INSTALL_DIR: /opt/hostedtoolcache/dotnet
+  NUGET_PACKAGES: /opt/hostedtoolcache/nuget
 
 jobs:
   build:
@@ -58,6 +61,10 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
+      # GitVersion is a .NET tool; Gitea's runner image has no .NET.
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 10.0.x
       - uses: gittools/actions/gitversion/setup@v4
         with:
           versionSpec: 6.x