The Chinese Digispark clones are very cheap and have a female USB connector which is good but they ship with RESET enabled which means that PB5 is not available for use.
To perform the change it is necessary to change the HFuse configuration of the ATTiny85.
I have used AVeRCADE with USBasp firmware for doing that, but any ISP programmer will do fine. The connections to a 10 pin are show below. However it is possible to use other methods, for example using an Arduino (link).
The command for programming the High fuse to its correct configuration is:
avrdude -c usbasp -p t85 -U hfuse:w:0x5f:mIf everything works fine you should see something like that