update everything to 2021 edition

exercise/closures_iterators/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "closures_iterators"
 version = "0.1.0"
-authors = ["Nathan Stocks <nathan@agileperception.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

exercise/docs/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "docs"
 version = "0.1.0"
-authors = ["Nathan Stocks <nathan@agileperception.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

exercise/errors/Cargo.toml

@@ -1,8 +1,7 @@
 [package]
 name = "aquarium"
 version = "0.1.0"
-authors = ["Nathan Stocks <nathan@agileperception.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 # I thought you might want this for your library...

exercise/idiomatic/Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "idiomatic"
 version = "0.1.0"
-authors = ["Nathan Stocks <nathan@agileperception.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]

exercise/logging/Cargo.toml

@@ -1,8 +1,7 @@
 [package]
 name = "frogger"
 version = "0.1.0"
-authors = ["Nathan Stocks <nathan@agileperception.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 # I'm glad you came to add the `log` dependency! I got it all ready for you, just uncomment:

exercise/testing/Cargo.toml

@@ -1,8 +1,7 @@
 [package]
 name = "testing"
 version = "0.1.0"
-authors = ["Nathan Stocks <nathan@agileperception.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 

exercise/threads_channels/Cargo.toml

@@ -1,8 +1,7 @@
 [package]
 name = "threads_channels"
 version = "0.1.0"
-authors = ["Nathan Stocks <nathan@agileperception.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 crossbeam = "0.8"

exercise/traits/Cargo.toml

@@ -1,8 +1,7 @@
 [package]
 name = "traits"
 version = "0.1.0"
-authors = ["Nathan Stocks <nathan@agileperception.com>"]
-edition = "2018"
+edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html