MountTag hashing using ":" instead of "\0" separator

Using \0 as a separator makes the hash hard to reproduce in environments
that do not allow NUL bytes in strings. This affects, for example, NixOS
configurations that generate filesystem mount definitions directly rather
than using cloud-init.

Signed-off-by: Alain Lehmann <alain.lehmann@gmail.com>

Author: ciderale

pkg/limayaml/defaults.go

@@ -95,7 +95,7 @@ func MACAddress(uniqueID string) string {
 // MountTag generates a stable mount tag from location and mountPoint.
 // Both paths are hashed to handle the same location mounted to multiple mount points.
 func MountTag(location, mountPoint string) string {
-	sha := sha256.Sum256([]byte(location + "\x00" + mountPoint))
+	sha := sha256.Sum256([]byte(location + ":" + mountPoint))
 	return fmt.Sprintf("lima-%x", sha[0:8])
 }