Use same CMake minimum version in DownloadProject configuration

We already have a top-level minimum requirement for CMake >= 3.8, so
don't need to specify a lower requirement in a file included from the top
level.

Having a requirement as low as 2.8.2 broke building on newer version of
CMake, which error with "Compatibility with CMake < 3.5 has been removed
from CMake." (seen in GitHub runners with Ubuntu 24.04).

Author: tautschnig

.github/workflows/pull-request-checks.yaml

@@ -51,7 +51,7 @@ jobs:
       - name: Build with make
         run: |
           git clone https://github.com/conp-solutions/riss riss.git
-          cmake -Hriss.git -Briss.git/release -DCMAKE_BUILD_TYPE=Release
+          cmake -Hriss.git -Briss.git/release -DCMAKE_BUILD_TYPE=Release -DCMAKE_POLICY_VERSION_MINIMUM=3.5
           make -C riss.git/release riss-coprocessor-lib-static -j${{env.linux-vcpus}}
           make -C src -j${{env.linux-vcpus}} CXX="ccache g++" LIBS="$PWD/riss.git/release/lib/libriss-coprocessor.a -lpthread" IPASIR=$PWD/riss.git/riss
           make -C jbmc/src -j${{env.linux-vcpus}} CXX="ccache g++" LIBS="$PWD/riss.git/release/lib/libriss-coprocessor.a -lpthread" IPASIR=$PWD/riss.git/riss

cmake/DownloadProject.CMakeLists.cmake.in

@@ -1,7 +1,7 @@
 # Distributed under the OSI-approved MIT License.  See accompanying
 # file LICENSE or https://github.com/Crascit/DownloadProject for details.
 
-cmake_minimum_required(VERSION 2.8.2)
+cmake_minimum_required(VERSION 3.8)
 
 project(${DL_ARGS_PROJ}-download NONE)