make nightly latest links more readable

Author: Roberto Sora

Diff for: README.md

@@ -47,13 +47,13 @@ These builds are generated once a day from `master` branch starting at 01:00 GMT
 
 In order to get the latest nightly build for your platform use the following links: 
 
-- **Linux 64 bit**: https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Linux_64bit.tar.gz
-- **Linux 32 bit**: https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Linux_32bit.tar.gz
-- **Linux ARM 64 bit**: https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Linux_ARM64.tar.gz
-- **Linux ARM 32 bit**: https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Linux_ARMv7.tar.gz
-- **Windows 64 bit**: https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Windows_64bit.zip
-- **Windows 32 bit**: https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Windows_32bit.zip
-- **Mac OSX**: https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_macOS_64bit.tar.gz
+- [Linux 64 bit](https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Linux_64bit.tar.gz)
+- [Linux 32 bit](https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Linux_32bit.tar.gz)
+- [Linux ARM 64 bit](https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Linux_ARM64.tar.gz)
+- [Linux ARM 32 bit](https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Linux_ARMv7.tar.gz)
+- [Windows 64 bit](https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Windows_64bit.zip)
+- [Windows 32 bit](https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_Windows_32bit.zip)
+- [Mac OSX](https://downloads.arduino.cc/arduino-cli/nightly/arduino-cli_nightly-latest_macOS_64bit.tar.gz)
 
 These links redirect to latest generated builds replacing `latest` with the latest available build
 date, using the format YYYYMMDD (i.e for 2019/Aug/06 `latest` is replaced with `20190806` )