Initial attempt at adding an ubuntu based container image (#48)

Co-authored-by: Lol3rrr <lol3r@lol3r.net>

.goreleaser.yml

@@ -46,6 +46,14 @@ dockers:
     goarch: amd64
     build_flag_templates:
       - "--platform=linux/amd64"
+  - image_templates:
+      - "itzg/rcon-cli:{{ .Version }}-ubuntu-amd64"
+    dockerfile: Dockerfile.ubuntu
+    use: buildx
+    goos: linux
+    goarch: amd64
+    build_flag_templates:
+      - "--platform=linux/amd64"
   - image_templates:
       - "itzg/rcon-cli:{{ .Version }}-arm64"
     dockerfile: Dockerfile.release
@@ -54,6 +62,14 @@ dockers:
     goarch: arm64
     build_flag_templates:
       - "--platform=linux/arm64"
+  - image_templates:
+      - "itzg/rcon-cli:{{ .Version }}-ubuntu-arm64"
+    dockerfile: Dockerfile.ubuntu
+    use: buildx
+    goos: linux
+    goarch: arm64
+    build_flag_templates:
+      - "--platform=linux/arm64"
   - image_templates:
       - "itzg/rcon-cli:{{ .Version }}-armv7"
     dockerfile: Dockerfile.release
@@ -63,6 +79,15 @@ dockers:
     goarm: '7'
     build_flag_templates:
       - "--platform=linux/arm/v7"
+  - image_templates:
+      - "itzg/rcon-cli:{{ .Version }}-ubuntu-armv7"
+    dockerfile: Dockerfile.ubuntu
+    use: buildx
+    goos: linux
+    goarch: arm
+    goarm: '7'
+    build_flag_templates:
+      - "--platform=linux/arm/v7"
 docker_manifests:
   - name_template: "itzg/rcon-cli:latest"
     image_templates:
@@ -74,6 +99,11 @@ docker_manifests:
       - "itzg/rcon-cli:{{ .Version }}-amd64"
       - "itzg/rcon-cli:{{ .Version }}-arm64"
       - "itzg/rcon-cli:{{ .Version }}-armv7"
+  - name_template: "itzg/rcon-cli:{{ .Version }}-ubuntu"
+    image_templates:
+      - "itzg/rcon-cli:{{ .Version }}-ubuntu-amd64"
+      - "itzg/rcon-cli:{{ .Version }}-ubuntu-arm64"
+      - "itzg/rcon-cli:{{ .Version }}-ubuntu-armv7"
 scoops:
   - bucket:
       owner: itzg

Dockerfile.ubuntu

@@ -0,0 +1,3 @@
+FROM ubuntu:22.04
+COPY rcon-cli /usr/bin/rcon-cli
+ENTRYPOINT ["/usr/bin/rcon-cli"]