fix: should not publish tap-snapshot folder

- Add `tap-snapshot` folder to `.npmignore`
- Fixes #461

PR-URL: #471
Credit: @ruyadorno
Close: #471
Reviewed-by: @claudiahdz

Author: ruyadorno

.npmignore

@@ -6,6 +6,7 @@ npm-debug.log
 node_modules/marked
 node_modules/marked-man
 node_modules/tap
+tap-snapshots
 node_modules/.bin
 node_modules/npm-registry-mock
 /npmrc