manifest: readme: use https

GitHub disabled the git protocol as of Jan 11, 2022
See https://github.blog/2021-09-01-improving-git-protocol-security-github/#no-more-unauthenticated-git

Author: Tortel

README.mkdn

@@ -11,7 +11,7 @@ CipherOS is a Android Custom OS, Based On AOSP & Fueled by Lineage, Striving to
 
 ```bash
 # Initialize repo
-repo init -u git://github.com/CipherOS/android_manifest.git -b eleven
+repo init -u https://github.com/CipherOS/android_manifest.git -b eleven
 
 # Sync 
 repo sync -c --force-sync --optimized-fetch --no-tags --no-clone-bundle --prune -j$(nproc --all)