Fix some CMake documentation typos (#616)

The quick start instructions for CMake mention the "master"
git branch which has been replaced by "main" in the current
repo.

The main CMakeLists.txt documents how to integrate a
custom port. Fix a typo in the suggested CMake code.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1d4a779..09bd4bd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -217,7 +217,7 @@
     "   target_include_directories(freertos_kernel_port\n"
     "     PUBLIC\n"
     "      .)\n"
-    "   taget_link_libraries(freertos_kernel_port\n"
+    "   target_link_libraries(freertos_kernel_port\n"
     "     PRIVATE\n"
     "       freertos_kernel)")
 endif()
diff --git a/README.md b/README.md
index 5674872..025a135 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@
 ```cmake
 FetchContent_Declare( freertos_kernel
   GIT_REPOSITORY https://github.com/FreeRTOS/FreeRTOS-Kernel.git
-  GIT_TAG        master #Note: Best practice to use specific git-hash or tagged version
+  GIT_TAG        main #Note: Best practice to use specific git-hash or tagged version
 )
 ```