gbp: Build Bullseye image

.Jenkinsfile

@@ -16,6 +16,21 @@ pipeline {
             }
         }
 
+        stage('Build gbp (Bullseye)') {
+            steps {
+                script {
+                    def deb = docker.build("evolix/gbp:build${env.BUILD_ID}", "gbp")
+                    def deb = docker.build("evolix/php:build${env.BUILD_ID}", "-f php/Dockerfile.bullseye gbp")
+                    deb.inside {
+                        sh 'gbp --version'
+                    }
+                 /* No crendentials yet
+                    deb.push('bullseye')
+                  */
+                }
+            }
+        }
+
         stage('Build shellcheck') {
             steps {
                 script {

.drone.yml

@@ -14,6 +14,18 @@ steps:
     repo: evolix/gbp
     tags: latest
 
+- name: build gbp (Bullseye)
+  image: plugins/docker
+  depends_on: []
+  settings:
+    username:
+      from_secret: docker_username
+    password:
+      from_secret: docker_password
+    dockerfile: gbp/Dockerfile.bullseye
+    repo: evolix/gbp
+    tags: bullseye
+
 - name: build shellcheck
   image: plugins/docker
   depends_on: []

gbp/Dockerfile.bullseye

@@ -0,0 +1,11 @@
+FROM debian:bullseye-slim
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+	build-essential \
+        debhelper \
+        dh-exec \
+        git-buildpackage \
+        equivs \
+        devscripts \
+    && rm -rf /var/lib/apt/lists/*