Revert: Use -Werror in CI (#237) (#249)

It seems my `-Werror` flag addition was waiting until the next time CI
thought
it was necessary to rebuild DuckDB to blow up our build. This reverts
the
change for now to fix the build on the main branch.

.github/workflows/build_and_test.yaml

@@ -112,7 +112,7 @@ jobs:
         id: build
         run: |
           pushd duckdb
-          make -j8 install CFLAGS=-Werror CXXFLAGS=-Werror
+          make -j8 install
 
       - name: Run make installcheck
         id: installcheck