Fix cmake deprecation failure coming from 3rd party (#279)

* Update json commit

* Align cmake min version across the project

* Update cmake in tests

Author: sovrasov

src/cpp/CMakeLists.txt

@@ -37,7 +37,9 @@ find_package(OpenVINO REQUIRED
              COMPONENTS Runtime Threading)
 
 include(FetchContent)
-FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz)
+FetchContent_Declare(json GIT_REPOSITORY https://github.com/nlohmann/json.git
+                          GIT_TAG d41ca94fa85d5119852e2f7a3f94335cc7cb0486  # PR #4709, fixes cmake deprecation warnings
+                    )
 FetchContent_MakeAvailable(json)
 
 file(GLOB MODELS_SOURCES ./models/src/*.cpp)

tests/cpp/accuracy/CMakeLists.txt

@@ -54,7 +54,9 @@ endif()
 include(CMakeParseArguments)
 include(FetchContent)
 
-FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.2/json.tar.xz)
+FetchContent_Declare(json GIT_REPOSITORY https://github.com/nlohmann/json.git
+                          GIT_TAG d41ca94fa85d5119852e2f7a3f94335cc7cb0486  # PR #4709, fixes cmake deprecation warnings
+                    )
 FetchContent_Declare(googletest
     GIT_REPOSITORY https://github.com/google/googletest.git
     GIT_TAG a7f443b80b105f940225332ed3c31f2790092f47  # latest main

tests/cpp/cmake/common.cmake

@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
-cmake_minimum_required(VERSION 3.11)
+cmake_minimum_required(VERSION 3.26)
 
 macro(add_test)
     set(oneValueArgs NAME OPENCV_VERSION_REQUIRED)

tests/cpp/precommit/CMakeLists.txt

@@ -53,7 +53,9 @@ endif()
 include(CMakeParseArguments)
 include(FetchContent)
 
-FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.2/json.tar.xz)
+FetchContent_Declare(json GIT_REPOSITORY https://github.com/nlohmann/json.git
+                          GIT_TAG d41ca94fa85d5119852e2f7a3f94335cc7cb0486  # PR #4709, fixes cmake deprecation warnings
+                    )
 FetchContent_Declare(googletest
     GIT_REPOSITORY https://github.com/google/googletest.git
     GIT_TAG a7f443b80b105f940225332ed3c31f2790092f47  # latest main