Add LD_LIBRARY_PATH to RuboCop workflow for Oracle 23 client

The ruby-oci8 gem's extconf.rb compiles and runs a test program to
determine OCI_MAJOR_VERSION. Without LD_LIBRARY_PATH set, the program
cannot find libclntsh.so.23.1 at runtime, causing the build to fail.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: yahonda

.github/workflows/rubocop.yml

@@ -10,6 +10,8 @@ jobs:
   build:
 
     runs-on: ubuntu-latest
+    env:
+      LD_LIBRARY_PATH: /usr/lib/oracle/23/client64/lib
 
     steps:
     - uses: actions/checkout@v4