Update to cmake 3.29.6

.gitlab-ci.yml

 variables:
   PREBUILD_CMAKE_VERSION: 3.18.2
-  CMAKE_VERSION: 3.28.3
+  CMAKE_VERSION: 3.29.6
 
 workflow:
   rules:

README.md

@@ -3,5 +3,5 @@
 Pipeline to build recent version of Cmake for our legacy CentOS 6 32 and 64 bits platform.
 
 Allows to build Cmake for:
-* CentOS 6.10 64 bits: [cmake-3.28.3-linux-x86_64.zip](https://gitlab.synchrotron-soleil.fr/software-control-system/devtools/cmake/-/jobs/artifacts/3.28.3/download?job=linux-x86_64)
-* CentOS 6.10 32 bits: [cmake-3.28.3-linux-i686.zip](https://gitlab.synchrotron-soleil.fr/software-control-system/devtools/cmake/-/jobs/artifacts/3.28.3/download?job=linux-i686)
+* CentOS 6.10 64 bits: [cmake-3.29.6-linux-x86_64.zip](https://gitlab.synchrotron-soleil.fr/software-control-system/devtools/cmake/-/jobs/artifacts/3.29.6/download?job=linux-x86_64)
+* CentOS 6.10 32 bits: [cmake-3.29.6-linux-i686.zip](https://gitlab.synchrotron-soleil.fr/software-control-system/devtools/cmake/-/jobs/artifacts/3.29.6/download?job=linux-i686)