fix: bump min code coverage to 78% (#153)

Author: andriisoldatenko

codecov.yml

@@ -1,12 +1,12 @@
 coverage:
-  range: 76..100
+  range: 78..100
   round: down
   precision: 2
   status:
     project:  # measuring the overall project coverage
       default:  # context, you can create multiple ones with custom titles
         enabled: yes  # must be yes|true to enable this status
-        target: 76  # specify the target coverage for each commit status
+        target: 78  # specify the target coverage for each commit status
         #   option: "auto" (must increase from parent commit or pull request base)
         #   option: "X%" a static target percentage to hit
         if_not_found: success  # if parent is not found report status as success, error, or failure