Clang: Update LLVM/Clang version in the README

Fixes: QTCREATORBUG-22103
Change-Id: Ic83923ded4ad9a91fb189b60ab43ca93426ee9a0
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

README.md

@@ -34,9 +34,10 @@ Prerequisites:
     * Python 3.5 or later (optional, needed for the python enabled debug helper)
 * On Mac OS X: latest Xcode
 * On Linux: g++ 5.3 or later
-* LLVM/Clang 6.0.0 or later (optional, needed for the Clang Code Model, see the
-  section "Get LLVM/Clang for the Clang Code Model")
-    * CMake (only for manual builds of LLVM/Clang)
+* LLVM/Clang 7.0.0 or later (optional, needed for the Clang Code Model, Clang Tools, ClangFormat,
+  Clang PCH Manager and Clang Refactoring plugins, see the section
+  "Get LLVM/Clang for the Clang Code Model")
+* CMake (only for manual builds of LLVM/Clang)
 * Qbs 1.7.x (optional, sources also contain Qbs itself)
 
 The installed toolchains have to match the one Qt was compiled with.
@@ -224,7 +225,7 @@ or using shadow builds.
 ## Get LLVM/Clang for the Clang Code Model
 
 The Clang Code Model depends on the LLVM/Clang libraries. The currently
-supported LLVM/Clang version is 6.0.
+supported LLVM/Clang version is 7.0.
 
 ### Prebuilt LLVM/Clang packages
 
@@ -251,9 +252,9 @@ GCC 4 binaries. On Ubuntu, you can download the package from
 http://apt.llvm.org/ with:
 
    wget -O - http://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-   sudo apt-add-repository "deb http://apt.llvm.org/`lsb_release -cs`/ llvm-toolchain-`lsb_release -cs`-6.0 main"
+   sudo apt-add-repository "deb http://apt.llvm.org/`lsb_release -cs`/ llvm-toolchain-`lsb_release -cs`-7.0 main"
    sudo apt-get update
-   sudo apt-get install llvm-6.0 libclang-6.0-dev
+   sudo apt-get install llvm-7.0 libclang-7.0-dev
 
 There is a workaround to set _GLIBCXX_USE_CXX11_ABI to 1 or 0, but we recommend
 to download the package from http://apt.llvm.org/.