Ignore src/cert.pem (#425)

Author: shibd

.npmignore

@@ -16,6 +16,7 @@
 # specific language governing permissions and limitations
 # under the License.
 #
+.idea
 .github
 build-support
 docs
@@ -33,6 +34,9 @@ tslint.json
 tstest.ts
 typedoc.json
 
+# pem
+src/cert.pem
+
 # license
 license-checker-config.json
 license-header.txt