deps: update to pcre2 0.2.4

0.2.4 updates to PCRE2 10.42 and has a few other nice changes. For
example, when `utf` is enabled, the crate will always set the
PCRE2_MATCH_INVALID_UTF option. That means we no longer need to do
transcoding or UTF-8 validity checks.

Because of this, we actually get to remove one of the two uses of
`unsafe` in ripgrep's `main` program.

(This also updates a couple other dependencies for convenience.)

crates/pcre2/Cargo.toml

@@ -15,4 +15,4 @@ edition = "2018"
 
 [dependencies]
 grep-matcher = { version = "0.1.6", path = "../matcher" }
-pcre2 = "0.2.3"
+pcre2 = "0.2.4"