update hookshot passkey.pem path according to docs

https://github.com/Half-Shot/matrix-hookshot/issues/133#issuecomment-1007541580

roles/matrix-bridge-hookshot/templates/config.yml.j2

@@ -82,7 +82,7 @@ passFile:
   # A passkey used to encrypt tokens stored inside the bridge.
   # Run openssl genpkey -out passkey.pem -outform PEM -algorithm RSA -pkeyopt rsa_keygen_bits:4096 to generate
   #
-  passkey.pem
+  /data/passkey.pem
 bot:
   # (Optional) Define profile information for the bot user
   #