Make regex an optional dependency (#659)

Co-authored-by: Dylan Anthony <[email protected]>

Author: dbanty

Cargo.lock

@@ -26,7 +26,7 @@ client = ["rand"]
 # and macros actually expand features (and extern crate) where they are used!
 debug-logs = ["dep:log"]
 test = ["client"]
-UNSTABLE_metrics = ["sentry-types/UNSTABLE_metrics"]
+UNSTABLE_metrics = ["sentry-types/UNSTABLE_metrics", "regex"]
 UNSTABLE_cadence = ["dep:cadence", "UNSTABLE_metrics"]
 
 [dependencies]
@@ -36,7 +36,7 @@ itertools = "0.13.0"
 log = { version = "0.4.8", optional = true, features = ["std"] }
 once_cell = "1"
 rand = { version = "0.8.1", optional = true }
-regex = "1.7.3"
+regex = { version = "1.7.3" , optional = true}
 sentry-types = { version = "0.33.0", path = "../sentry-types" }
 serde = { version = "1.0.104", features = ["derive"] }
 serde_json = { version = "1.0.46" }