fix: generate bigint type instead of BigInt

.changeset/healthy-ways-juggle.md

@@ -0,0 +1,5 @@
+---
+'@hey-api/openapi-ts': patch
+---
+
+fix: generate bigint type instead of BigInt

packages/openapi-ts/src/plugins/@hey-api/typescript/plugin.ts

@@ -418,7 +418,7 @@ const numberTypeToIdentifier = ({
   if (schema.type === 'integer' && schema.format === 'int64') {
     // TODO: parser - add ability to skip type transformers
     if (context.config.plugins['@hey-api/transformers']?.bigInt) {
-      return compiler.typeReferenceNode({ typeName: 'BigInt' });
+      return compiler.typeReferenceNode({ typeName: 'bigint' });
     }
   }
 

packages/openapi-ts/test/__snapshots__/2.0.x/plugins/@hey-api/transformers/type-format/types.gen.ts

@@ -2,7 +2,7 @@
 
 export type Foo = {
     bar?: number;
-    foo: BigInt;
+    foo: bigint;
     id: string;
 };
 

packages/openapi-ts/test/__snapshots__/3.0.x/plugins/@hey-api/transformers/type-format/types.gen.ts

@@ -2,7 +2,7 @@
 
 export type Foo = {
     bar?: number;
-    foo: BigInt;
+    foo: bigint;
     id: string;
 };
 

packages/openapi-ts/test/__snapshots__/3.1.x/plugins/@hey-api/transformers/type-format/types.gen.ts

@@ -2,7 +2,7 @@
 
 export type Foo = {
     bar?: number;
-    foo: BigInt;
+    foo: bigint;
     id: string;
 };