It is better to use the repository field in Cargo.toml (#1655)

To allow [Crates.io](https://crates.io/) , [lib.rs](https://lib.rs/) and
the [Rust Digger](https://rust-digger.code-maven.com/) to link to it.
See [the
manifest](https://doc.rust-lang.org/cargo/reference/manifest.html#the-repository-field)
for the explanation.

Signed-off-by: Gábor Szabó <gabor@szabgab.com>

Cargo.toml

@@ -2,7 +2,7 @@
 name = "solang"
 version = "0.3.3"
 authors = ["Sean Young <sean@mess.org>", "Lucas Steuernagel <lucas.tnagel@gmail.com>", "Cyrill Leutwiler <bigcyrill@hotmail.com>"]
-homepage = "https://github.com/hyperledger/solang"
+repository = "https://github.com/hyperledger/solang"
 documentation = "https://solang.readthedocs.io/"
 license = "Apache-2.0"
 build = "build.rs"

solang-parser/Cargo.toml

@@ -2,7 +2,7 @@
 name = "solang-parser"
 version = "0.3.3"
 authors = ["Sean Young <sean@mess.org>", "Lucas Steuernagel <lucas.tnagel@gmail.com>", "Cyrill Leutwiler <bigcyrill@hotmail.com>"]
-homepage = "https://github.com/hyperledger/solang"
+repository = "https://github.com/hyperledger/solang"
 documentation = "https://solang.readthedocs.io/"
 license = "Apache-2.0"
 build = "build.rs"