keil5 pack 离线包安装：安装过keil5软件后，直接双击pack 离线包即可。
F1pack包 https://keilpack.azureedge.net/pack/Keil.STM32F1xx_DFP.2.3.0.pack
F2pack包 https://keilpack.azureedge.net/pack/Keil.STM32F2xx_DFP.2.9.0.pack
F3pack包 https://keilpack.azureedge.net/pack/Keil.STM32F3xx_DFP.2.1.0.pack
F4pack包 https://keilpack.azureedge.net/pack/Keil.STM32F4xx_DFP.2.13.0.pack