mark EpollEvent methods const (#2656)

* mark `EpollEvent` methods `const`

* Create PULL_REQUEST_ID.changed.md

* Rename PULL_REQUEST_ID.changed.md to 2656.changed.md

#2656

* Update epoll.rs

needs a more recent Rust version

Author: skaunov

changelog/2656.changed.md

@@ -0,0 +1 @@
+changed `EpollEvent` methods to be `const`

src/sys/epoll.rs

@@ -49,7 +49,7 @@ pub struct EpollEvent {
 }
 
 impl EpollEvent {
-    pub fn new(events: EpollFlags, data: u64) -> Self {
+    pub const fn new(events: EpollFlags, data: u64) -> Self {
         EpollEvent {
             event: libc::epoll_event {
                 events: events.bits() as u32,
@@ -66,7 +66,7 @@ impl EpollEvent {
         EpollFlags::from_bits(self.event.events as c_int).unwrap()
     }
 
-    pub fn data(&self) -> u64 {
+    pub const fn data(&self) -> u64 {
         self.event.u64
     }
 }