* updating test to use the Java RESTEasy echo api client (#17367)
* regenerated samples
* set source and target to 1.8 to fix workflow failure, adapted parser
* fix: change indent style to tab in the mustache to generate Go code
* docs: standardize the language names for code blocks
* docs: change indent style to tab in the code blocks
* update: regenerate samples
* `./bin/generate-samples.sh ./bin/configs/*.yaml`
