Only require Rust 1.63. (#257)

This PR switches to routecore release 0.3.1 so we only require Rust 1.63.

Author: partim

.github/workflows/ci.yml

@@ -7,7 +7,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
-        rust: [1.65.0, stable, beta, nightly]
+        rust: [1.63.0, stable, beta, nightly]
     steps:
     - name: Checkout repository
       uses: actions/checkout@v1

Cargo.toml

@@ -2,7 +2,7 @@
 name = "rpki"
 version = "0.16.1-dev"
 edition = "2018"
-rust-version = "1.65"
+rust-version = "1.63"
 authors = ["The NLnet Labs RPKI Team <[email protected]>"]
 description = "A library for validating and creating RPKI data."
 documentation = "https://docs.rs/rpki/"
@@ -27,7 +27,7 @@ log             = "0.4.7"
 openssl         = { version = "0.10.23", optional = true }
 quick-xml       = { version = "0.23.0", optional = true }
 ring            = { version = "0.16.11", optional = true }
-routecore       = { git = "https://github.com/NLnetLabs/routecore.git" }
+routecore       = "0.3.1"
 serde           = { version = "1.0.103", optional = true, features = [ "derive" ] }
 serde_json      = { version = "1.0.40", optional = true }
 tokio           = { version = "1.0", optional = true, features = ["io-util",  "net", "rt", "sync", "time"] }