Change the identify file path from hardcoded absolute to user based

## Issue

The issue is that a hardcoded full path is in a github action something like `/home/runner` if you need that file inside of a docker build system you can not simply mount that file into the container. You need to copy the file, sed it (string replace) and then mount it.

If we would use something like a "home dir" placeholder this would work out of the box.

Not sure if ~ works in all cases but %d should.

https://linux.die.net/man/5/ssh_config

index.js

@@ -66,7 +66,7 @@ try {
 
         const sshConfig = `\nHost key-${sha256}.github.com\n`
                               + `    HostName github.com\n`
-                              + `    IdentityFile ${homeSsh}/key-${sha256}\n`
+                              + `    IdentityFile ~/.ssh/key-${sha256}\n`
                               + `    IdentitiesOnly yes\n`;
 
         fs.appendFileSync(`${homeSsh}/config`, sshConfig);