Update googletest to 1.18.0 and SIMDe to 0.8.2.

Googletest 1.18 asks for CMake 3.13 or newer, so configuring the tests no longer warns that CMake compatibility below 3.10 is deprecated.

Co-authored-by: Cursor <cursoragent@cursor.com>

thirdparty/simde/.travis.yml

@@ -7,8 +7,7 @@ jobs:
   - name: POWER9
     if: branch != master OR type == pull_request
     arch: ppc64le
-    compiler:
-    - clang
+    compiler: clang
     env:
     - CC="clang"
     - CXX="clang++"
@@ -22,8 +21,7 @@ jobs:
   - name: z/Arch
     if: branch != master OR type == pull_request
     arch: s390x
-    compiler:
-    - gcc
+    compiler: gcc
     env:
     - CC="gcc"
     - CXX="g++"