REVIEW: Add a sentence and footnote with link on the schema browser

https://rubinobs.atlassian.net/browse/PUB-182?focusedCommentId=570464

C702.tex

@@ -140,6 +140,7 @@ \section{Felis in the Rubin Observatory}
 These represent a set of public-facing data catalogs used by the Rubin Science Platform (RSP) to provide access to the data.
 The files are managed in a Git repository and versioned as a set with Git tags.
 Changes to the schemas are validated in GitHub workflows, ensuring that they are well-defined, with any errors flagged to the user.
+An online schema browser is available for viewing the latest versions of the SDM Schemas, as well as the history of changes \footnote{\url{https://sdm-schemas.lsst.io}}.
 Rubin Observatory's SIAv2 service \citep{P920_adassxxxiv} uses Felis to define the SIAv2 data model and ensure that the resultant VOTable is conformant.
 
 \section{Future Work}