Fix typo in behat flag

Author: swissspidy

.github/workflows/reusable-testing.yml

@@ -536,7 +536,7 @@ jobs:
           WP_CLI_TEST_DBTYPE: ${{ matrix.dbtype || 'mysql' }}
           WP_CLI_TEST_DBSOCKET: '${{ steps.setup-mysql.outputs.base-dir }}/tmp/mysql.sock'
           WP_CLI_TEST_COVERAGE: ${{ matrix.coverage }}
-          BEHAT_ARGS: ${{ format( '{0}', runner.debug && '--format-pretty' ) }}
+          BEHAT_ARGS: ${{ format( '{0}', runner.debug && '--format=pretty' ) }}
         run: |
           composer behat -- $BEHAT_ARGS || composer behat-rerun -- $BEHAT_ARGS