Update splunk-otel-javaagent to latest (#6944)

* Update splunk-otel-javaagent to latest

* Add changelog

---------

Co-authored-by: Paulo Janotti <[email protected]>

Author: srv-gh-o11y-gdi

.chloggen/update-javaagent.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: 'enhancement'
+
+# The name of the component, or a single word describing the area of concern, (e.g. crosslink)
+component: 'javaagent'
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Update Splunk Distribution of OpenTelemetry Java to version [2.21.1](https://github.com/signalfx/splunk-otel-java/releases/tag/v2.21.1)
+
+# One or more tracking issues related to the change
+issues: [6944]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

instrumentation/packaging/java-agent-release.txt

@@ -1 +1 @@
-v2.20.1
+v2.21.1