BF: add locales into the buildenv docker

For some reason build
https://github.com/datalad/git-annex/actions/runs/17224263724/job/48865784238
did fail with

    dpkg-checkbuilddeps: error: unmet build dependencies: locales
    dpkg-buildpackage: error: build dependencies/conflicts unsatisfied; aborting
    make: *** [Makefile:197: dpkg-buildpackage-S] Error 3

which may be added for standalone, so lets just add it too

Author: yarikoptic

.github/workflows/tools/containers/buildenv-git-annex/Dockerfile

@@ -27,8 +27,8 @@ RUN set -ex; \
     apt-get update -qq; \
     export DEBIAN_FRONTEND=noninteractive; \
     apt-get build-dep -y -q git-annex; \
-    # Needed additional tools
-    apt-get install -y devscripts quilt; \
+    # Needed additional tools etc
+    apt-get install -y devscripts quilt locales; \
     # Some helper utilities just in case
     apt-get install -y vim wget strace time ncdu gnupg curl procps datalad pigz less tree; \
     apt-get clean; \