build: gitpod docker file updated

.gitpod.Dockerfile

@@ -1,14 +1,10 @@
 FROM trainiteu/gitpod-cpp
 
-# Add clang-12 and clang-15 apt repositories
+# Add clang apt repositories
 RUN lsb_rel=`lsb_release -cs` \
-  && sudo add-apt-repository "deb http://apt.llvm.org/${lsb_rel}/ llvm-toolchain-${lsb_rel}-13 main" \
-  && sudo add-apt-repository "deb http://apt.llvm.org/${lsb_rel}/ llvm-toolchain-${lsb_rel}-14 main" \
-  && sudo add-apt-repository "deb http://apt.llvm.org/${lsb_rel}/ llvm-toolchain-${lsb_rel} main"
+  && sudo add-apt-repository "deb http://apt.llvm.org/${lsb_rel}/ llvm-toolchain-${lsb_rel}-16 main"
 
-# Install older compilers supported by the project as well as clang-format-15 for code formatting
+# Install older compilers supported by the project
 RUN sudo install-packages \
-  g++-10 \
-  g++-11 \
-  clang-13 \
-  clang-14
+  g++-12 \
+  clang-16