Bump the version to 0.5.2-rc.1 for the release candidate

Version only, and thrown away after the candidate reports. The candidate
exercises the packaging matrix on a real tag: the six package and release
workflows, the prerelease Release object, the AUR build with its check()
and namcap gate, and a real upgrade from the published 0.5.1 packages.

Cargo.lock

@@ -1163,7 +1163,7 @@ checksum = "9844ddc3a6e533d62bba727eb6c28b5d360921d5175e9ff0f1e621a5c590a4d5"
 
 [[package]]
 name = "fips"
-version = "0.5.2-dev"
+version = "0.5.2-rc.1"
 dependencies = [
  "arc-swap",
  "bech32 0.12.0",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "fips"
-version = "0.5.2-dev"
+version = "0.5.2-rc.1"
 edition = "2024"
 description = "A distributed, decentralized network routing protocol for mesh nodes connecting over arbitrary transports"
 license = "MIT"