exclude readme from drone triggers, add sha sums

.drone.yml

@@ -10,6 +10,9 @@ steps:
 - name: build_img
   image: debian:buster
   privileged: true
+  settings:
+    exclude:
+    - "readme.md"
   volumes:
   - name: builds
     path: /tl-builds
@@ -26,6 +29,15 @@ steps:
   - git clone --recurse-submodules https://tildegit.org/tildelinux/lb-config config
   - lb build 
   - mv live-image-amd64.img /tl-builds/tildelinux.img
+- name: sha512sum
+  image: debian:buster
+  privileged: true
+  volumes:
+  - name: builds
+    path: /tl-builds
+  commands:
+  - cd /tl-builds
+  - sha512sum * > SHA512SUMS
 
 volumes:
 - name: builds