fix: add terraform setup to GH workflow (#57)

Author: markmcmurray-sysdig

.github/workflows/ci-pull-request.yaml

@@ -47,6 +47,8 @@ jobs:
       uses: actions/setup-go@v2
       with:
         go-version: ${{ env.GO_VERSION }}
+    - name: Set up Terraform
+      uses: hashicorp/setup-terraform@v3
     - name: Check out code
       uses: actions/checkout@v2
     - name: Cache modules