I have created my first D&D5e character and have just achieved level 5.

Race: Wood Elf 
Class: Fighter
Background: Soldier
Skills: Acrobatics and Survival from the fighter class, 
and Athletics and Intimidation from my background.

When my character reaches 5th level my proficiency bonus increases from +2 to +3.

Do I also increase the proficiency in the two skills gained from my background?