Add cargo to build armhf

snap/snapcraft.yaml

@@ -79,8 +79,8 @@ grade: stable
 confinement: strict
 
 architectures:
-  - build-on: amd64
-  - build-on: arm64
+  # - build-on: amd64
+  # - build-on: arm64
   - build-on: armhf
     #- build-on: ppc64el
 
@@ -190,6 +190,7 @@ parts:
       - zlib1g-dev
       - on armhf:
         - rustc
+        - cargo
     stage-packages:
       - freeglut3
       - ffmpeg