Ensured the correct CA key and CA certificate is used during signing process. It's been working based on default assumptions from the openssl configuration, but it's worth being explicit when doing these operations. Also removed a redundant -sha256

.gitlab/ci/build_archiso.sh

@@ -241,7 +241,6 @@ create_ephemeral_codesigning_keys() {
     # Create the Certificate Authority
     openssl req \
         -newkey rsa:4096 \
-        -sha256 \
         -nodes \
         -x509 \
         -new \
@@ -280,6 +279,8 @@ EOF
         -days 2 \
         -notext \
         -md sha256 \
+        -keyfile "${ca_key}" \
+        -cert "${ca_cert}" \
         -in "${codesigning_cert}.csr" \
         -out "${codesigning_cert}"