added docker manifest

Author: fabiodcorreia

manifest.tmpl

@@ -0,0 +1,22 @@
+image: fabiodcorreia/base-python:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}latest{{/if}}
+{{#if build.tags}}
+tags:
+{{#each build.tags}}
+  - {{this}}
+{{/each}}
+{{/if}}
+manifests:
+  - image: fabiodcorreia/base-python:{{#if build.tag}}{{trimPrefix "v" build.tag}}-{{/if}}amd64
+    platform:
+      architecture: amd64
+      os: linux
+  - image: fabiodcorreia/base-python:{{#if build.tag}}{{trimPrefix "v" build.tag}}-{{/if}}arm64v8
+    platform:
+      architecture: arm64
+      os: linux
+      variant: v8
+  - image: fabiodcorreia/base-python:{{#if build.tag}}{{trimPrefix "v" build.tag}}-{{/if}}arm32v7
+    platform:
+      architecture: arm
+      os: linux
+      variant: v7