Use global.json to specify .NET version (#3007)

Rather than specifying this in `ci.yml`, specify it in the `global.json` file. This allows us to share the version amongst several workflows (and ADO pipelines) without needing to synchronize them.

Author: Porges

.github/workflows/ci.yml

@@ -20,7 +20,6 @@ env:
   SCCACHE_CACHE_SIZE: 1G
   ACTIONS_CACHE_KEY_DATE: 2022-11-21-02
   CI: true
-  DOTNET_VERSION: 7.0.x
 
 jobs:
   agent:
@@ -269,8 +268,8 @@ jobs:
       - name: Setup .NET Core SDK
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: ${{env.DOTNET_VERSION}}
-          dotnet-quality: "ga"
+          # use global.json to install the correct version
+          global-json-file: global.json
       - name: Install dependencies
         run: |
           cd src/ApiService/
@@ -364,8 +363,8 @@ jobs:
       - name: Setup .NET Core SDK
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: ${{env.DOTNET_VERSION}}
-          dotnet-quality: "ga"
+          # use global.json to install the correct version
+          global-json-file: global.json
       - run: src/ci/dotnet-fuzzing-tools.sh
         shell: bash
       - uses: actions/upload-artifact@v3
@@ -379,8 +378,8 @@ jobs:
       - name: Setup .NET Core SDK
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: ${{env.DOTNET_VERSION}}
-          dotnet-quality: "ga"
+          # use global.json to install the correct version
+          global-json-file: global.json
       - run: src/ci/dotnet-fuzzing-tools.ps1
         shell: pwsh
       - uses: actions/upload-artifact@v3

global.json

@@ -0,0 +1,6 @@
+{
+    "sdk": {
+        "version": "7.0.100",
+        "rollForward": "latestFeature"
+    }
+}