Update to cmake 3.26.4

.gitlab-ci.yml

 variables:
   PREBUILD_CMAKE_VERSION: 3.18.2
-  CMAKE_VERSION: 3.26.2
+  CMAKE_VERSION: 3.26.4
 
 workflow:
   rules:

README.md

@@ -3,7 +3,7 @@
 Pipeline to build recent version of Cmake for our legacy CentOS 32 bits platform.
 
 Cmake provides independent 64 bits Linux distribution that works on CentOS 6 64 bits but they are not available for 32 bits:
-* https://cmake.org/files/v3.26/cmake-3.26.2-linux-x86_64.tar.gz
+* https://cmake.org/files/v3.26/cmake-3.26.4-linux-x86_64.tar.gz
 
 Allows to build Cmake for:
-* CentOS 6.10 32 bits: [cmake-3.26.2-linux-i686.zip](https://gitlab.synchrotron-soleil.fr/software-control-system/devtools/cmake/-/jobs/artifacts/3.26.2/download?job=linux-i686)
+* CentOS 6.10 32 bits: [cmake-3.26.4-linux-i686.zip](https://gitlab.synchrotron-soleil.fr/software-control-system/devtools/cmake/-/jobs/artifacts/3.26.4/download?job=linux-i686)