Bump xgrammar from 0.1.11 to 0.1.18 (vllm-project#1043)

Bumps [xgrammar](https://github.com/mlc-ai/xgrammar) from 0.1.11 to
0.1.18.


Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Michał Kuligowski <[email protected]>

Author: dependabot[bot]

requirements/common.txt

@@ -22,7 +22,7 @@ lm-format-enforcer >= 0.10.11, < 0.11
 llguidance >= 0.7.9, < 0.8.0; platform_machine == "x86_64" or platform_machine == "arm64" or platform_machine == "aarch64"
 outlines == 0.1.11
 lark == 1.2.2
-xgrammar == 0.1.17; platform_machine == "x86_64" or platform_machine == "aarch64"
+xgrammar == 0.1.18; platform_machine == "x86_64" or platform_machine == "aarch64"
 typing_extensions >= 4.10
 filelock >= 3.16.1 # need to contain https://github.com/tox-dev/filelock/pull/317
 partial-json-parser # used for parsing partial JSON outputs