chore(.github): pin go to 1.20.0 for tinygo 0.27.0 compatibility

Signed-off-by: Vaughn Dice <[email protected]>

.github/workflows/build.yml

@@ -6,7 +6,7 @@ on:
 
 jobs:
   build:
-    runs-on: "ubuntu-latest"
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v3
 
@@ -20,6 +20,11 @@ jobs:
           unzip wasi-vfs-cli-x86_64-unknown-linux-gnu.zip
           mv wasi-vfs /usr/local/bin
 
+      - uses: actions/setup-go@v5
+        with:
+          go-version: '^1.20.0'
+          check-latest: false
+
       - name: Install tinygo
         run: |
           wget https://github.com/tinygo-org/tinygo/releases/download/v0.27.0/tinygo_0.27.0_amd64.deb