Temporarily remove Julia 1.9

Author: davidanthoff

.github/workflows/jlpkgbutler-ci-pr-workflow.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        julia-version: ['1.0', '1.1', '1.2', '1.3', '1.4', '1.5', '1.6', '1.7', '1.8', '1.9']
+        julia-version: ['1.0', '1.1', '1.2', '1.3', '1.4', '1.5', '1.6', '1.7', '1.8']
         julia-arch: [x64, x86]
         os: [ubuntu-latest, windows-latest, macOS-latest]
         exclude: