Constrain docker.yml publish to n.n.n tags only (#43)

Ignore suffix builds like n.n.n-xxxx

Author: johnspurlock-skymethod

.github/workflows/docker.yml

@@ -3,7 +3,7 @@ name: docker
 on:
   push:
     branches: ["main"]
-    tags: ["*"]
+    tags: ["[0-9]+.[0-9]+.[0-9]+"]
   pull_request:
     branches: ["main"]