Change git clone to use https and NOT ssh

It is less confusing to give https based cloning instructions for
public repositories.
Avoid the typical "fatal: could not read from remote repository"
issue.

Signed-off-by: Tomás González <tomasagustin.gonzalezorlando@arm.com>

src/getting_started/parsec_tool_use.md

@@ -22,7 +22,7 @@ cargo install parsec-tool
 For building it, use the following commands:
 
 ```
-git clone git@github.com:parallaxsecond/parsec-tool.git
+git clone https://github.com/parallaxsecond/parsec-book.git
 cd parsec-tool
 cargo build
 ```