links http -> https (#3010)

more secure

Author: Rotzbua

docs/platformio.md

@@ -1,11 +1,11 @@
 Installation instructions for using PlatformIO
 =================================================
 
-- [What is PlatformIO?](http://docs.platformio.org/en/latest/what-is-platformio.html?utm_source=github&utm_medium=arduino-esp32)
-- [PlatformIO IDE](http://platformio.org/platformio-ide?utm_source=github&utm_medium=arduino-esp32)
-- [PlatformIO Core](http://docs.platformio.org/en/latest/core.html?utm_source=github&utm_medium=arduino-esp32) (command line tool)
-- [Advanced usage](http://docs.platformio.org/en/latest/platforms/espressif32.html?utm_source=github&utm_medium=arduino-esp32) -
+- [What is PlatformIO?](https://docs.platformio.org/en/latest/what-is-platformio.html?utm_source=github&utm_medium=arduino-esp32)
+- [PlatformIO IDE](https://platformio.org/platformio-ide?utm_source=github&utm_medium=arduino-esp32)
+- [PlatformIO Core](https://docs.platformio.org/en/latest/core.html?utm_source=github&utm_medium=arduino-esp32) (command line tool)
+- [Advanced usage](https://docs.platformio.org/en/latest/platforms/espressif32.html?utm_source=github&utm_medium=arduino-esp32) -
   custom settings, uploading to SPIFFS, Over-the-Air (OTA), staging version
-- [Integration with Cloud and Standalone IDEs](http://docs.platformio.org/en/latest/ide.html?utm_source=github&utm_medium=arduino-esp32) -
+- [Integration with Cloud and Standalone IDEs](https://docs.platformio.org/en/latest/ide.html?utm_source=github&utm_medium=arduino-esp32) -
   Cloud9, Codeanywhere, Eclipse Che (Codenvy), Atom, CLion, Eclipse, Emacs, NetBeans, Qt Creator, Sublime Text, VIM, Visual Studio, and VSCode
-- [Project Examples](http://docs.platformio.org/en/latest/platforms/espressif32.html?utm_source=github&utm_medium=arduino-esp32#examples)
+- [Project Examples](https://docs.platformio.org/en/latest/platforms/espressif32.html?utm_source=github&utm_medium=arduino-esp32#examples)