Bump alpine from 3.15.3 to 3.15.4 (#429)

Bumps alpine from 3.15.3 to 3.15.4.

---
updated-dependencies:
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Dockerfile

@@ -2,7 +2,7 @@
 # BUILD CONTAINER
 ##
 
-FROM alpine:3.15.3 as certs
+FROM alpine:3.15.4 as certs
 
 RUN \
 apk add --no-cache ca-certificates