manpage: change OPTIONS to FLAGS

Signed-off-by: Ma Shimiao <[email protected]>

Author: Ma Shimiao

cmd/oci-create-runtime-bundle/oci-create-runtime-bundle.1.md

@@ -14,7 +14,7 @@ oci-create-runtime-bundle \- Create an OCI runtime bundle
 Also translates the referenced config from application/vnd.oci.image.config.v1+json to a
 runtime-spec-compatible `dest/config.json`.
 
-# OPTIONS
+# FLAGS
 **--help**
   Print usage statement
 

cmd/oci-image-validate/oci-image-validate.1.md

@@ -12,7 +12,7 @@ oci-image-validate \- Validate one or more image files
 `oci-image-validate` validates the given file(s) against the OCI image specification.
 
 
-# OPTIONS
+# FLAGS
 **--help**
   Print usage statement
 

cmd/oci-unpack/oci-unpack.1.md

@@ -11,7 +11,7 @@ oci-unpack \- Unpack an image or image source layout
 # DESCRIPTION
 `oci-unpack` validates an application/vnd.oci.image.manifest.v1+json and unpacks its layered filesystem to `dest`.
 
-# OPTIONS
+# FLAGS
 **--help**
   Print usage statement