Shorten the keyword `polynomial-commitments` to `commitments` (#77)

Cargo.toml

@@ -14,7 +14,7 @@ authors = [
 description = "A library for constructing polynomial commitment schemes for use in zkSNARKs"
 repository = "https://github.com/arkworks-rs/poly-commit"
 documentation = "https://docs.rs/ark-poly-commit/"
-keywords = ["cryptography", "polynomial-commitments", "elliptic-curves", "pairing"]
+keywords = ["cryptography", "commitments", "elliptic-curves", "pairing"]
 categories = ["cryptography"]
 include = ["Cargo.toml", "src", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
 license = "MIT/Apache-2.0"