Properly setup Go version in update workflow

To prevent false `go.mod` modifications.

Signed-off-by: Hidde Beydals <hello@hidde.co>

.github/workflows/update.yaml

@@ -13,7 +13,10 @@ jobs:
     steps:
       - name: Check out code
         uses: actions/checkout@v2
-
+      - name: Setup Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.16.x
       - name: Update component versions
         id: update
         run: |