Update lecture slides and demo notes

Author: uekerman

05_testing_and_ci/boost_testing_intro_slides.md

@@ -52,7 +52,7 @@ slideOptions:
 - Powerful unit test framework
 - Sometimes called (the) **Unit Test Framework** (UTF) or **Boost.Test**
     - Valid on all slides: `namespace utf = boost::unit_test;`
-- [List of contributors and maintainers](https://www.boost.org/doc/libs/1_81_0/libs/test/doc/html/boost_test/acknowledgements.html)
+- [List of contributors and maintainers](https://www.boost.org/doc/libs/1_87_0/libs/test/doc/html/boost_test/acknowledgements.html)
 
 ---
 
@@ -190,4 +190,4 @@ Which behavior do you then expect and why?
 
 ## Further Reading
 
-- [Documentation of Boost Unit Test Framework](https://www.boost.org/doc/libs/1_78_0/libs/test/doc/html/index.html)
+- [Documentation of Boost Unit Test Framework](https://www.boost.org/doc/libs/1_87_0/libs/test/doc/html/index.html)

05_testing_and_ci/boost_testing_sidemade_demo.md

@@ -46,6 +46,7 @@ Repository: [testing boost exercise – demo-start branch](https://github.com/Si
     find_package(Boost 1.71 REQUIRED unit_test_framework)
     file(GLOB_RECURSE TEST_FILES CONFIGURE_DEPENDS tests/*.cpp)
     add_executable(testsidemade "${TEST_FILES}")
+    set_property(target testsidemade PROPERTY CXX_STANDARD 11)
     target_link_libraries(testsidemade PRIVATE Boost::unit_test_framework)
     add_test(NAME "MatrixSolverTests" COMMAND ${CMAKE_CURRENT_BINARY_DIR}/testsidemade)
     ```