Do not impose leadnig slash in the URL

This artificial requirement was introduced by nock#1391.

lib/interceptor.js

@@ -28,19 +28,6 @@ module.exports = class Interceptor {
    */
   constructor(scope, uri, method, requestBody, interceptorOptions) {
     const uriIsStr = typeof uri === 'string'
-    // Check for leading slash. Uri can be either a string or a regexp, but
-    // When enabled filteringScope ignores the passed URL entirely so we skip validation.
-
-    if (
-      !scope.scopeOptions.filteringScope &&
-      uriIsStr &&
-      !uri.startsWith('/') &&
-      !uri.startsWith('*')
-    ) {
-      throw Error(
-        `Non-wildcard URL path strings must begin with a slash (otherwise they won't match anything) (got: ${uri})`
-      )
-    }
 
     if (!method) {
       throw new Error(