Merge #14393: doc: add missing apt-get install

86eddd4 doc: miss install (poiuty)

Pull request description:

Tree-SHA512: 2d9a3a5be1f68584e97c7429eb04514456c859422452a2d16bb35b8b1b54a0e4d059444a981d5c753d063bc8edfbe1a3c49740fa96998f0818e3ef5c6c6ff7d5

Author: MarcoFalke

doc/build-unix.md

@@ -74,7 +74,7 @@ Build requirements:
 
 Now, you can either build from self-compiled [depends](/depends/README.md) or install the required dependencies:
 
-    sudo apt-get libssl-dev libevent-dev libboost-system-dev libboost-filesystem-dev libboost-chrono-dev libboost-test-dev libboost-thread-dev
+    sudo apt-get install libssl-dev libevent-dev libboost-system-dev libboost-filesystem-dev libboost-chrono-dev libboost-test-dev libboost-thread-dev
 
 BerkeleyDB is required for the wallet.