Update heck to 0.4.0

Cargo.lock

@@ -101,12 +101,9 @@ checksum = "d7afe4a420e3fe79967a00898cc1f4db7c8a49a9333a29f8a4bd76a253d5cd04"
 
 [[package]]
 name = "heck"
-version = "0.3.1"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "20564e78d53d2bb135c343b3f47714a56af2061f1c928fdb541dc7b9fdd94205"
-dependencies = [
- "unicode-segmentation",
-]
+checksum = "2540771e65fc8cb83cd6e8a237f70c319bd5c29f78ed1084ba5d50eeac86f7f9"
 
 [[package]]
 name = "hermit-abi"
@@ -387,12 +384,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "unicode-segmentation"
-version = "1.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e83e153d1053cbb5a118eeff7fd5be06ed99153f00dbcd8ae310c5fb2b22edc0"
-
 [[package]]
 name = "unicode-width"
 version = "0.1.8"

Cargo.toml

@@ -30,7 +30,7 @@ tempfile = "3.0"
 toml = "0.5"
 proc-macro2 = "1"
 quote = "1"
-heck = "0.3"
+heck = "0.4"
 
 [dependencies.syn]
 version = "1.0.3"

src/bindgen/rename.rs

@@ -69,11 +69,11 @@ impl RenameRule {
 
         Cow::Owned(match self {
             RenameRule::None => return Cow::Borrowed(text),
-            RenameRule::GeckoCase => context.to_str().to_owned() + &text.to_camel_case(),
+            RenameRule::GeckoCase => context.to_str().to_owned() + &text.to_upper_camel_case(),
             RenameRule::LowerCase => text.to_lowercase(),
             RenameRule::UpperCase => text.to_uppercase(),
-            RenameRule::PascalCase => text.to_camel_case(),
-            RenameRule::CamelCase => text.to_mixed_case(),
+            RenameRule::PascalCase => text.to_pascal_case(),
+            RenameRule::CamelCase => text.to_upper_camel_case(),
             RenameRule::SnakeCase => text.to_snake_case(),
             RenameRule::ScreamingSnakeCase => text.to_shouty_snake_case(),
             RenameRule::QualifiedScreamingSnakeCase => {