Use latest version of Mbed OS master

Patater · Patater · commit ccd9d8e9ee3a · 2019-05-09T13:09:35.000+01:00
diff --git a/mbed-os.lib b/mbed-os.lib
@@ -1 +1 @@
-https://github.com/ARMmbed/mbed-os/#0f959dbe4749c20416236e4fe1dac5692cbe18ab
+https://github.com/ARMmbed/mbed-os/

Original file line number	Diff line number	Diff line change
`@@ -1 +1 @@`
`1`		`-https://github.com/ARMmbed/mbed-os/#0f959dbe4749c20416236e4fe1dac5692cbe18ab`
	`1`	`+https://github.com/ARMmbed/mbed-os/`