Let nvim cancel if a merge kicks off a new build

Author: binarypie

.github/workflows/build-nvim-dev.yml

@@ -4,6 +4,10 @@
 
 name: Build nvim-dev Image
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 on:
   push:
     branches: