Update source/manuals/programming-languages/docker.html.md.erb

source/manuals/programming-languages/docker.html.md.erb

@@ -69,6 +69,9 @@ If you specify both the tag and the digest, then the digest takes precedence.
 The standard implies that you may only specify one or the other.  Do not specify
 both as the behaviour may vary across different platforms.
 
+Instead, the recommended way to keep track of the intended version is to add it in a line above FROM as a comment.
+
+Please double-check that the digest and the commented version are consistent each time you upgrade, as dependabot does not have perfect capability at either identifying the magnitude of the upgrade, or necessarily updating the commented pin.
 ```
 # alpine:3.9
 FROM alpine@sha256:769fddc7cc2f0a1c35abb2f91432e8beecf83916c421420e6a6da9f8975464b6