Although the values doesn't exceed the absolute maximum ratings, there's no guaranteed maximum voltage drop for PIC IO-pins with 20 mA load current. An external driver is recommended.
The standard solution is a BJT transistor (no darlington because it has too high voltage drop for a 5V relay) with base series resistor or a MOSFET, together with a freewheeling diode.
You can save the freewheeling diode by using a BJT in common collector circuit, provided the 5V supply doesn't drop more than 5%, you get sufficient margin above the required 3.75 minmal relay pull-in voltage.