Update kubeconform -h output (#260)

In particular, the `-output pretty` option is missing.

Readme.md

@@ -103,39 +103,39 @@ $ go install github.com/yannh/kubeconform/cmd/kubeconform@latest
 
 ```
 $ kubeconform -h
-Usage: ./bin/kubeconform [OPTION]... [FILE OR FOLDER]...
+Usage: kubeconform [OPTION]... [FILE OR FOLDER]...
   -cache string
-        cache schemas downloaded via HTTP to this folder
+    	cache schemas downloaded via HTTP to this folder
   -debug
-        print debug information
+    	print debug information
   -exit-on-error
-        immediately stop execution when the first error is encountered
-  -h    show help information
+    	immediately stop execution when the first error is encountered
+  -h	show help information
   -ignore-filename-pattern value
-        regular expression specifying paths to ignore (can be specified multiple times)
+    	regular expression specifying paths to ignore (can be specified multiple times)
   -ignore-missing-schemas
-        skip files with missing schemas instead of failing
+    	skip files with missing schemas instead of failing
   -insecure-skip-tls-verify
-        disable verification of the server\'s SSL certificate. This will make your HTTPS connections insecure
+    	disable verification of the server's SSL certificate. This will make your HTTPS connections insecure
   -kubernetes-version string
-        version of Kubernetes to validate against, e.g.: 1.18.0 (default "master")
+    	version of Kubernetes to validate against, e.g.: 1.18.0 (default "master")
   -n int
-        number of goroutines to run concurrently (default 4)
+    	number of goroutines to run concurrently (default 4)
   -output string
-        output format - json, junit, tap, text (default "text")
+    	output format - json, junit, pretty, tap, text (default "text")
   -reject string
-        comma-separated list of kinds or GVKs to reject
+    	comma-separated list of kinds or GVKs to reject
   -schema-location value
-        override schemas location search path (can be specified multiple times)
+    	override schemas location search path (can be specified multiple times)
   -skip string
-        comma-separated list of kinds or GVKs to ignore
+    	comma-separated list of kinds or GVKs to ignore
   -strict
-        disallow additional properties not in schema or duplicated keys
+    	disallow additional properties not in schema or duplicated keys
   -summary
-        print a summary at the end (ignored for junit output)
-  -v    show version information
+    	print a summary at the end (ignored for junit output)
+  -v	show version information
   -verbose
-        print results for all resources (ignored for tap and junit output)
+    	print results for all resources (ignored for tap and junit output)
 ```
 
 ### Usage examples