Bump library/httpd in /testserver/proxy

Bumps library/httpd from 2.4.58-alpine to 2.4.59-alpine.

---
updated-dependencies:
- dependency-name: library/httpd
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

testserver/proxy/Dockerfile

@@ -1,4 +1,4 @@
-FROM docker.io/library/httpd:2.4.58-alpine
+FROM docker.io/library/httpd:2.4.59-alpine
 RUN sed -i \
         -e 's/^#\(LoadModule .*mod_proxy.so\)/\1/' \
         -e 's/^#\(LoadModule .*mod_proxy_connect.so\)/\1/' \