Deal with charset

Close #231

src/scripts/import-open-api.ts

@@ -195,12 +195,14 @@ export const getResReqTypes = (
       if (isReference(res)) {
         return getRef(res.$ref);
       } else {
-        if (res.content && res.content["application/json"]) {
-          const schema = res.content["application/json"].schema!;
-          return resolveValue(schema);
-        } else if (res.content && res.content["application/octet-stream"]) {
-          const schema = res.content["application/octet-stream"].schema!;
-          return resolveValue(schema);
+        if (res.content) {
+          for (let contentType of Object.keys(res.content)) {
+            if (contentType.startsWith("application/json") || contentType.startsWith("application/octet-stream")) {
+              const schema = res.content[contentType].schema!;
+              return resolveValue(schema);
+            }
+          }
+          return "void";
         } else {
           return "void";
         }

src/scripts/tests/import-open-api.test.ts

@@ -737,6 +737,22 @@ describe("scripts/import-open-api", () => {
       expect(getResReqTypes(responses)).toEqual("FieldListResponse");
     });
 
+    it("should return the type of application/json;charset=utf-8", () => {
+      const responses: Array<[string, ResponseObject]> = [
+        [
+          "200",
+          {
+            description: "An array of schema fields",
+            content: {
+              "application/json;charset=utf-8": { schema: { $ref: "#/components/schemas/FieldListResponse" } },
+            },
+          },
+        ],
+      ];
+
+      expect(getResReqTypes(responses)).toEqual("FieldListResponse");
+    });
+
     it("should return the type of application/octet-stream if we don't have application/json response", () => {
       const responses: Array<[string, ResponseObject]> = [
         [