Switch to PEP-604 syntax in python2 stubs (#5915)

Signed-off-by: oleg.hoefling <oleg.hoefling@gmail.com>

stdlib/@python2/posix.pyi

@@ -1,5 +1,5 @@
 from _typeshed import FileDescriptorLike
-from typing import IO, AnyStr, Dict, List, Mapping, NamedTuple, Optional, Sequence, Tuple, TypeVar, Union
+from typing import IO, AnyStr, Dict, List, Mapping, NamedTuple, Sequence, Tuple, TypeVar
 
 error = OSError
 
@@ -100,7 +100,7 @@ def chown(path: unicode, uid: int, gid: int) -> None: ...
 def chroot(path: unicode) -> None: ...
 def close(fd: int) -> None: ...
 def closerange(fd_low: int, fd_high: int) -> None: ...
-def confstr(name: Union[str, int]) -> str: ...
+def confstr(name: str | int) -> str: ...
 def ctermid() -> str: ...
 def dup(fd: int) -> int: ...
 def dup2(fd: int, fd2: int) -> None: ...
@@ -178,7 +178,7 @@ def statvfs(path: unicode) -> statvfs_result: ...
 def stat_float_times(fd: int) -> None: ...
 def strerror(code: int) -> str: ...
 def symlink(source: unicode, link_name: unicode) -> None: ...
-def sysconf(name: Union[str, int]) -> int: ...
+def sysconf(name: str | int) -> int: ...
 def system(command: unicode) -> int: ...
 def tcgetpgrp(fd: int) -> int: ...
 def tcsetpgrp(fd: int, pg: int) -> None: ...
@@ -190,7 +190,7 @@ def uname() -> Tuple[str, str, str, str, str]: ...
 def unlink(path: unicode) -> None: ...
 def unsetenv(varname: str) -> None: ...
 def urandom(n: int) -> str: ...
-def utime(path: unicode, times: Optional[Tuple[int, int]]) -> None: ...
+def utime(path: unicode, times: Tuple[int, int] | None) -> None: ...
 def wait() -> int: ...
 
 _r = Tuple[float, float, int, int, int, int, int, int, int, int, int, int, int, int, int, int]