docs: fix tutorial link in INSTALL.md

docs/INSTALL.md

@@ -171,7 +171,7 @@ lnd --bitcoin.active --bitcoin.testnet --debuglevel=debug --neutrino.active --ne
 If you are on testnet, run this command after `btcd` has finished syncing.
 Otherwise, replace `--bitcoin.testnet` with `--bitcoin.simnet`. If you
 installing `lnd` in preparation for the
-[tutorial](//dev.lightning.community/tutorial), you may skip this step.
+[tutorial](http://dev.lightning.community/tutorial), you may skip this step.
 ```
 lnd --bitcoin.active --bitcoin.testnet --debuglevel=debug --bitcoin.rpcuser=kek --bitcoin.rpcpass=kek --externalip=X.X.X.X
 ```