Bump GSON to 2.9.1
<felix.version>7.0.1</felix.version>
<felix.log.version>1.0.1</felix.log.version>
<findbugs.version>3.0.2</findbugs.version> <!-- Should be kept in sync with guava -->
- <gson.version>2.8.9</gson.version>
+ <gson.version>2.9.1</gson.version>
<hdrhistogram.version>2.1.12</hdrhistogram.version>
<jetty.version>9.4.48.v20220622</jetty.version>
<jetty-alpn.version>1.1.3.v20160715</jetty-alpn.version>
