Bump showdown from 1.8.6 to 1.8.7 (#397)

Bumps [showdown](https://github.com/showdownjs/showdown) from 1.8.6 to 1.8.7.
- [Release notes](https://github.com/showdownjs/showdown/releases)
- [Changelog](https://github.com/showdownjs/showdown/blob/master/CHANGELOG.md)
- [Commits](showdownjs/showdown@1.8.6...1.8.7)

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

Author: dependabot[bot]

package-lock.json

@@ -63,7 +63,7 @@
     "redux": "^3.7.2",
     "redux-mock-store": "^1.5.1",
     "redux-saga": "^0.15.6",
-    "showdown": "^1.8.6",
+    "showdown": "^1.8.7",
     "typesafe-actions": "^1.1.2",
     "utility-types": "^2.0.0"
   },

package.json

@@ -9874,10 +9874,10 @@ shellwords@^0.1.1:
   resolved "https://registry.yarnpkg.com/shellwords/-/shellwords-0.1.1.tgz#d6b9181c1a48d397324c84871efbcfc73fc0654b"
   integrity sha512-vFwSUfQvqybiICwZY5+DAWIPLKsWO31Q91JSKl3UYv+K5c2QRPzn0qzec6QPu1Qc9eHYItiP3NdJqNVqetYAww==
 
-showdown@^1.8.6:
-  version "1.8.6"
-  resolved "https://registry.yarnpkg.com/showdown/-/showdown-1.8.6.tgz#91ea4ee3b7a5448aaca6820a4e27e690c6ad771c"
-  integrity sha1-kepO47elRIqspoIKTifmkMatdxw=
+showdown@^1.8.7:
+  version "1.8.7"
+  resolved "https://registry.yarnpkg.com/showdown/-/showdown-1.8.7.tgz#c4ccf300063adb0ef75a1b94b29a6cb6f7c36008"
+  integrity sha512-S1wyj80vu2lZZ7xm2ijr6e3VxHxPu8WfhTH7R6nelbIQeyl2g0ioEohS0YtFim8yAFMbQ8sQuXxiKvr10rKbTg==
   dependencies:
     yargs "^10.0.3"