[HIGH] CVE-2019-18887: Use constant time comparison in UriSigner

PKSA-sn9k-4yr8-6s9c CVE-2019-18887 GHSA-q8hg-pf8v-cxrv

Affected package: symfony/http-kernel

Affected version: >=2.2.0,<2.3.0|>=2.3.0,<2.4.0|>=2.4.0,<2.5.0|>=2.5.0,<2.6.0|>=2.6.0,<2.7.0|>=2.7.0,<2.8.0|>=2.8.0,<2.8.52|>=3.0.0,<3.1.0|>=3.1.0,<3.2.0|>=3.2.0,<3.3.0|>=3.3.0,<3.4.0|>=3.4.0,<3.4.35|>=4.0.0,<4.1.0|>=4.1.0,<4.2.0|>=4.2.0,<4.2.12|>=4.3.0,<4.3.8

Reported by:
GitHub, FriendsOfPHP/security-advisories