Remove extra environment variable (#516)

Author: kyleconroy

.github/workflows/ci.yml

@@ -32,7 +32,6 @@ jobs:
     - name: Test sqlc
       run: go test --tags=examples -v ./...
       env:
-        SQLC_EXPERIMENTAL_PARSER: on
         PG_USER: postgres
         PG_HOST: localhost
         PG_DATABASE: postgres