CI: github: do the AWS-LC weekly build with ERR=1

The weekly CI that tries new version of AWS-LC was not building with
ERR=1, which let us think that everything was good but there was in fact
new warning that we missed.

Add ERR=1 to the build so the CI will failed for any new warning.

.github/workflows/aws-lc.yml

@@ -33,7 +33,7 @@ jobs:
         run: env ${{ steps.get_aws_lc_release.outputs.result }} scripts/build-ssl.sh
       - name: Compile HAProxy
         run: |
-          make -j$(nproc) CC=gcc TARGET=linux-glibc \
+          make -j$(nproc) ERR=1 CC=gcc TARGET=linux-glibc \
             USE_OPENSSL_AWSLC=1 USE_QUIC=1 \
             SSL_LIB=${HOME}/opt/lib SSL_INC=${HOME}/opt/include \
             DEBUG="-DDEBUG_POOL_INTEGRITY" \