Adds a .gitignore for Python virtual environments. (opensearch-projec…

…t#4881)

Some projects such as the trace-analytics-sample-app and the current smoke tests use Python. Using Python virtual environments lets developers use these without affecting their local Python environment. Ignore .venv directories which Python virtual environments use.

Signed-off-by: David Venable <dlv@amazon.com>

.gitignore

@@ -13,3 +13,6 @@ gradle/tools
 # Ignore config file generated by test
 data-prepper-main/src/test/resources/logstash-filter.yaml
 data-prepper-main/src/test/resources/logstash-conf/logstash-filter.yaml
+
+# Python virtual environments
+.venv