fix: ignore bugged coverage lines

see gotwarlost/istanbul#690 for details

README.md

@@ -1,8 +1,7 @@
 # OpenRPC Utils For Javascript
 
 [![Dependabot Status](https://api.dependabot.com/badges/status?host=github&repo=open-rpc/schema-utils-js)](https://dependabot.com)
-
+[![codecov](https://codecov.io/gh/open-rpc/schema-utils-js/branch/master/graph/badge.svg)](https://codecov.io/gh/open-rpc/schema-utils-js)
 ### Contributing
 
 How to contribute, build and release are outlined in [CONTRIBUTING.md](CONTRIBUTING.md), [BUILDING.md](BUILDING.md) and [RELEASING.md](RELEASING.md) respectively. Commits in this repository follow the [CONVENTIONAL_COMMITS.md](CONVENTIONAL_COMMITS.md) specification.
-

src/generate-method-id.ts

@@ -12,6 +12,7 @@ export class ContentDescriptorNotFoundInMethodError extends Error {
    * @param contentDescriptor OpenRPC Content Descriptor that was expected to be in the method param.
    */
   constructor(public method: types.MethodObject, public contentDescriptor: types.ContentDescriptorObject) {
+    /* istanbul ignore next */
     super([
       "Content Descriptor not found in method.",
       `Method: ${JSON.stringify(method, undefined, "  ")}`,

src/method-call-validator/parameter-validation-error.ts

@@ -19,6 +19,7 @@ export default class MethodCallParameterValidationError extends Error {
     public receievedParam: any,
     private errors: ErrorObject[],
   ) {
+    /* istanbul ignore next */
     super([
       "Expected param in position ",
       paramIndex,

src/parse-open-rpc-document.ts

@@ -26,6 +26,7 @@ export class OpenRPCDocumentDereferencingError extends Error {
    * @param e The error that originated from jsonSchemaRefParser
    */
   constructor(e: Error) {
+    /* istanbul ignore next */
     super(`The json schema provided cannot be dereferenced. Received Error: \n ${e.message}`);
   }
 }

src/validate-open-rpc-document.ts

@@ -17,6 +17,7 @@ export class OpenRPCDocumentValidationError extends Error {
    * @param errors The errors received by ajv.errors.
    */
   constructor(private errors: Ajv.ErrorObject[]) {
+    /* istanbul ignore next */
     super([
       "Error validating OpenRPC Document against @open-rpc/meta-schema.",
       "The errors found are as follows:",