Fix submodules for github actions

- Use https so we don't have to set ssh-key

.github/workflows/pio_build.yml

@@ -8,6 +8,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
+        with:
+          submodules: true
       - uses: actions/cache@v3
         with:
           path: |

.gitmodules

@@ -1,6 +1,6 @@
 [submodule "src/mavlink"]
 	path = src/mavlink
-	url = git@github.com:uci-overRID/mavlink.git
+	url = https://github.com/uci-overRID/mavlink.git
 [submodule "src/opendroneid"]
 	path = src/opendroneid
-	url = git@github.com:opendroneid/opendroneid-core-c.git
+	url =  https://github.com/uci-overRID/opendroneid-core-c.git