Bump stringstream from 0.0.5 to 0.0.6 in /generator-exercise

Bumps [stringstream](https://github.com/mhart/StringStream) from 0.0.5 to 0.0.6.
- [Release notes](https://github.com/mhart/StringStream/releases)
- [Commits](https://github.com/mhart/StringStream/compare/v0.0.5...v0.0.6)

Signed-off-by: dependabot[bot] <support@github.com>

generator-exercise/package-lock.json

@@ -4529,9 +4529,9 @@
       }
     },
     "stringstream": {
-      "version": "0.0.5",
-      "resolved": "https://registry.npmjs.org/stringstream/-/stringstream-0.0.5.tgz",
-      "integrity": "sha1-TkhM1N5aC7vuGORjB3EKioFiGHg=",
+      "version": "0.0.6",
+      "resolved": "https://registry.npmjs.org/stringstream/-/stringstream-0.0.6.tgz",
+      "integrity": "sha512-87GEBAkegbBcweToUrdzf3eLhWNg06FJTebl4BVJz/JgWy8CvEr9dRtX5qWphiynMSQlxxi+QqN0z5T32SLlhA==",
       "dev": true
     },
     "strip-ansi": {