bump LINUX_BASE_IMAGE from ubuntu 18 to 22

Author: sbSteveK

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ env:
   BUILDER_SOURCE: releases
   BUILDER_HOST: https://d19elf31gohf1l.cloudfront.net
   PACKAGE_NAME: aws-crt-python
-  LINUX_BASE_IMAGE: ubuntu-18-x64
+  LINUX_BASE_IMAGE: ubuntu-22-x64
   RUN: ${{ github.run_id }}-${{ github.run_number }}
   CRT_CI_ROLE: ${{ secrets.CRT_CI_ROLE_ARN }}
   AWS_DEFAULT_REGION: us-east-1