add shasum create for releases bin files

Signed-off-by: MaxPeal <30347730+MaxPeal@users.noreply.github.com>

.travis.yml

@@ -14,7 +14,7 @@ env:
 
 script:
   - make binaries validate-all && TARGETPLATFORM="${CROSS_PLATFORMS}" ./hack/cross
-
+  - for i in ./out/*; do shasum --binary -a 256 "$i" >> "$i.sha256"; done
 
 deploy:
   - provider: script
@@ -32,4 +32,4 @@ deploy:
     on:
      repo: docker/buildx
      tags: true
-     condition: $TRAVIS_TAG =~ ^v[0-9]
+     condition: $TRAVIS_TAG =~ ^v[0-9]