Windows virtual environment: Use SSH binaries from the Git suite (#63)

* Use SSH binaries from the Git suite

* Try to kill the ssh-agent upon action termination on Windows as well

cleanup.js

@@ -1,10 +1,12 @@
-const core = require('@actions/core')
-const { execSync } = require('child_process')
+const core = require('@actions/core');
+const { execSync } = require('child_process');
+const { sshAgent } = require('./paths.js');
 
 try {
     // Kill the started SSH agent
-    console.log('Stopping SSH agent')
-    execSync('kill ${SSH_AGENT_PID}', { stdio: 'inherit' })
+    console.log('Stopping SSH agent');
+    execSync(sshAgent, ['-k'], { stdio: 'inherit' });
+
 } catch (error) {
     console.log(error.message);
     console.log('Error stopping the SSH agent, proceeding anyway');