Remove deprecated methods in IOHelpers class

[manusa]

Description

Part of #5778

The following methods must be removed from IOUtils:

• isJSONValid(String json)
  

  kubernetes-client/kubernetes-client-api/src/main/java/io/fabric8/kubernetes/client/utils/IOHelpers.java

  Lines 71 to 72 in 25ecf84

  	@Deprecated
  	public static boolean isJSONValid(String json) {

• convertYamlToJson(String yaml)
  

  kubernetes-client/kubernetes-client-api/src/main/java/io/fabric8/kubernetes/client/utils/IOHelpers.java

  Lines 85 to 86 in 25ecf84

  	@Deprecated
  	public static String convertYamlToJson(String yaml) {

• String convertToJson(String jsonOrYaml)
  

  kubernetes-client/kubernetes-client-api/src/main/java/io/fabric8/kubernetes/client/utils/IOHelpers.java

  Lines 93 to 94 in 25ecf84

  	@Deprecated
  	public static String convertToJson(String jsonOrYaml) {

[stale]

This issue has been automatically marked as stale because it has not had any activity since 90 days. It will be closed if no further activity occurs within 7 days. Thank you for your contributions!