rutime: Add a check_before_update field support

opencontainers/runtime-spec#1158

Signed-off-by: utam0k <[email protected]>

Author: utam0k

src/runtime/linux.rs

@@ -310,6 +310,10 @@ pub struct LinuxMemory {
     #[serde(skip_serializing_if = "Option::is_none")]
     /// Enables hierarchical memory accounting
     use_hierarchy: Option<bool>,
+
+    #[serde(skip_serializing_if = "Option::is_none")]
+    /// Enables checking if a new memory limit is lower
+    check_before_update: Option<bool>,
 }
 
 #[derive(