.gitlab-ci.yml: minor changes inside the .yml file.

+ ubuntu:21.10 added into the pipeline,
- ubuntu:20.10 removed from the pipeline,

+ misc/docker/ubuntu-21.10-amd64/Dockerfile added,
- misc/docker/ubuntu-20.10-amd64/Dockerfile removed.

.gitlab-ci.yml

@@ -164,9 +164,9 @@ docker_ubuntu-20_04-amd64:
     IMG_NAME: "ubuntu-20.04-amd64"
   <<: *docker_build
 
-docker_ubuntu-20_10-amd64:
+docker_ubuntu-21_10-amd64:
   variables:
-    IMG_NAME: "ubuntu-20.10-amd64"
+    IMG_NAME: "ubuntu-21.10-amd64"
   <<: *docker_build
 
 # GPG error
@@ -336,9 +336,9 @@ build-ubuntu-20_04-amd64:
   <<: *build-linux
   image: registry.nic.cz/labs/bird:ubuntu-20.04-amd64
 
-build-ubuntu-20_10-amd64:
+build-ubuntu-21_10-amd64:
   <<: *build-linux
-  image: registry.nic.cz/labs/bird:ubuntu-20.10-amd64
+  image: registry.nic.cz/labs/bird:ubuntu-21.10-amd64
 
 #build-ubuntu-21_04-amd64:
 #  <<: *build-linux
@@ -490,10 +490,11 @@ pkg-ubuntu-20.04-amd64:
   needs: [build-ubuntu-20_04-amd64]
   image: registry.nic.cz/labs/bird:ubuntu-20.04-amd64
 
-pkg-ubuntu-20.10-amd64:
+
+pkg-ubuntu-21.10-amd64:
   <<: *pkg-deb
-  needs: [build-ubuntu-20_10-amd64]
-  image: registry.nic.cz/labs/bird:ubuntu-20.10-amd64
+  needs: [build-ubuntu-21_10-amd64]
+  image: registry.nic.cz/labs/bird:ubuntu-21.10-amd64
 
 #pkg-ubuntu-21.04-amd64:
 #  <<: *pkg-deb

misc/docker/ubuntu-21.10-amd64/Dockerfile

@@ -1,9 +1,10 @@
-FROM ubuntu:20.10
+FROM ubuntu:21.10
 ENV DEBIAN_FRONTEND=noninteractive
 RUN sed -i 's/deb.debian.org/ftp.cz.debian.org/' /etc/apt/sources.list
 RUN apt-get -y update
 RUN apt-get -y upgrade
-RUN apt-get -y install \
+RUN apt-get -y --no-install-recommends install \
+	tzdata \
 	build-essential \
 	flex \
 	bison \