chore: append compat:gtest 1.18.0 (#553)

Co-authored-by: xpkgindex-update[bot] <xpkgindex-update@users.noreply.github.com>

Author: github-actions[bot]

pkgs/c/compat.gtest.lua

@@ -1,3 +1,10 @@
+local versions = {
+    ["1.18.0"] = {
+        url = "https://github.com/google/googletest/archive/refs/tags/v1.18.0.tar.gz",
+        sha256 = "6e3191c1455468b3fc35a417fb565c1c5071aee1b7e7f85e30cf48a98d37d8b5",
+    },
+}
+
 -- M6.x glob-aware Form B descriptor for gtest.
 -- All paths inside `mcpp = {}` are GLOBS relative to the verdir
 -- (~/.mcpp/registry/data/xpkgs/<idx>-x-gtest/<ver>/).  `*` matches any
@@ -36,6 +43,7 @@ package = {
                 },
                 sha256 = "7b42b4d6ed48810c5362c265a17faebe90dc2373c885e5216439d37927f02926",
             },
+            ["1.18.0"] = versions["1.18.0"],
         },
         macosx = {
             ["1.17.0"] = {
@@ -53,6 +61,7 @@ package = {
                 },
                 sha256 = "7b42b4d6ed48810c5362c265a17faebe90dc2373c885e5216439d37927f02926",
             },
+            ["1.18.0"] = versions["1.18.0"],
         },
         windows = {
             ["1.17.0"] = {
@@ -70,6 +79,7 @@ package = {
                 },
                 sha256 = "7b42b4d6ed48810c5362c265a17faebe90dc2373c885e5216439d37927f02926",
             },
+            ["1.18.0"] = versions["1.18.0"],
         },
     },