update docker base images and add git-filter-repo

- update base image to debian:bullseye
- add debian backports and install git-filter-repo from bullseye-backports
- update git version as filter repo requires git >=2.24.0

Signed-off-by: Akhil Mohan <akhilerm@gmail.com>

Dockerfile

@@ -12,12 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM debian:stretch
+FROM debian:bullseye
 MAINTAINER Stefan Schimanski <sttts@redhat.com>
+# debian backports are added so that git-filter-repo can be installed
+RUN echo deb http://deb.debian.org/debian bullseye-backports main >> /etc/apt/sources.list
 RUN apt-get update \
- && apt-get install -y -qq git=1:2.11.0-3+deb9u7 \
+ && apt-get install -y -qq git=1:2.30.2-1+deb11u2 \
  && apt-get install -y -qq mercurial \
- && apt-get install -y -qq ca-certificates curl wget jq vim tmux bsdmainutils tig gcc zip \
+ && apt-get install -y -qq ca-certificates curl wget jq vim tmux bsdmainutils tig gcc zip git-filter-repo/bullseye-backports \
  && rm -rf /var/lib/apt/lists/*
 
 ENV GOPATH="/go-workspace"