Bump alpine from 3.15.2 to 3.15.3 in /.ci/releaser/alpine (#819)

Bumps alpine from 3.15.2 to 3.15.3.

---
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>

.ci/releaser/alpine/Dockerfile

@@ -1,6 +1,6 @@
 # Initially copied from
 # https://github.com/jordansissel/fpm/blob/master/Dockerfile
-FROM alpine:3.15.2
+FROM alpine:3.15.3
 
 SHELL ["/bin/ash", "-eo", "pipefail", "-c"]