JRuby maintenance is limited - restrict to JRuby 10 support

Author: petergoldstein

.github/workflows/tests.yml

@@ -18,8 +18,7 @@ jobs:
           - '3.0'
           - '2.7'
           - '2.6'
-          - jruby-9.3
-          - jruby-9.4
+          - jruby-10
         memcached-version: ['1.5.22', '1.6.34']
 
     name: "Ruby ${{ matrix.ruby-version }} / Memcached ${{ matrix.memcached-version }}"