build: switch to https urls for submodules

Author: uerceg

.gitmodules

@@ -1,8 +1,8 @@
 [submodule "ext/android/sdk"]
 	path = ext/android/sdk
-	url = git@github.com:adjust/android_sdk.git
+	url = https://github.com/adjust/android_sdk.git
 	branch = master
 [submodule "ext/ios/sdk"]
 	path = ext/ios/sdk
-	url = git@github.com:adjust/ios_sdk.git
+	url = https://github.com/adjust/ios_sdk.git
 	branch = master