Add reminder to update UI tests in 18n readme
Add reminder to update UI tests in 18n readme

rvarshney/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,dillia23/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,pickettd/code-dot-org,rvarshney/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,pickettd/code-dot-org,pickettd/code-dot-org,pickettd/code-dot-org,pickettd/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org