Fix code signing script for MacOS builds

It is unclear whether the keychain preparation script failed due to
changes by Homebrew or due to the recent update to use MacOS 13 for
release builds. Regardless, older versions of either Homebrew or MacOS
are no longer relevant and all that matters is that the keychain
preparation script works again.

scripts/prepare_macos_keychain.sh

@@ -4,6 +4,7 @@
 # - https://docs.github.com/en/actions/deployment/deploying-xcode-applications/installing-an-apple-certificate-on-macos-runners-for-xcode-development
 # - https://localazy.com/blog/how-to-automatically-sign-macos-apps-using-github-actions
 # - https://federicoterzi.com/blog/automatic-code-signing-and-notarization-for-macos-apps-using-github-actions/
+# - https://github.com/lando/code-sign-action/
 
 # This script assumes that these environment variables are provided:
 # - RUNNER_TEMP (temporary directory provided by Github Actions runner)
@@ -21,9 +22,9 @@ security set-keychain-settings -lut 21600 $KEYCHAIN_PATH
 security unlock-keychain -p "$KEYCHAIN_PASSWORD" $KEYCHAIN_PATH
 
 # Decode and import signing certificate
-echo -n "$OPENEMV_MACOS_CERT_BASE64" | base64 --decode --output $OPENEMV_MACOS_CERT_PATH
+echo -n "$OPENEMV_MACOS_CERT_BASE64" | base64 --decode > $OPENEMV_MACOS_CERT_PATH
 security import $OPENEMV_MACOS_CERT_PATH -P "$OPENEMV_MACOS_CERT_PWD" -A -t cert -f pkcs12 -k $KEYCHAIN_PATH
-security list-keychain -d user -s $KEYCHAIN_PATH
+security list-keychains -d user -s $KEYCHAIN_PATH
 security find-identity -v -p codesigning
 
 # Allow codesign application to use signing key