Removes ruby 2.6

`activesupport` version 7.x does not support Ruby versions
older than 2.7.

Signed-off-by: M. Scott Ford <[email protected]>

Author: mscottford

.github/workflows/ruby.yml

@@ -18,7 +18,6 @@ jobs:
           - '3.1.4'
           - '3.0.6'
           - '2.7.7'
-          - '2.6.6'
 
     steps:
     - uses: actions/checkout@v3