prepare release 0.1.1

This is the first release under rust edition 2021. This update only contains minor efficiency improvements that take advantage of clippy recommendations and changes in edition 2021. There are no breaking api changes contained in this version, so it's only a minor version number increment

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mset"
-version = "0.1.0" # remember to update html_root_url crate attribute
+version = "0.1.1" # remember to update html_root_url crate attribute
 description = "A mset / multiset / bag implementation"
 keywords = ["mset", "multiset", "bag", "counter", "collection"]
 categories = ["data-structures", "mathematics"]

README.md

@@ -17,7 +17,7 @@ Add this to your `Cargo.toml`:
 
 ```toml
 [dependencies]
-mset = "0.1.0"
+mset = "0.1.1"
 ```
 
 Now, you can use  mset:

src/lib.rs

@@ -1,4 +1,4 @@
-#![doc(html_root_url = "https://docs.rs/mset/0.1.0")]
+#![doc(html_root_url = "https://docs.rs/mset/0.1.1")]
 //! A hash multiset implemented as a `HashMap` where the value is `usize`.
 //!
 //! A mset, multiset, or bag is a set that allows multiple occurances of an