Use Ruby 2.7.7 as the default

ashmckenzie · ashmckenzie · commit bf274412c8da · 2022-11-28T11:24:01.000+11:00
diff --git a/.tool-versions b/.tool-versions
@@ -1,2 +1,2 @@
-ruby 2.7.5
+ruby 2.7.7
 golang 1.18.7
