upgrade psycopg2 to latest (2.8.6) (#3133)

Co-authored-by: Miles Calabresi <mcalabresi1@gmail.com>

esp/requirements.txt

@@ -23,7 +23,7 @@ ipython==3.2.1 # Used for shell_plus
 Markdown==2.3.1 # Used in QSD
 numpy==1.7.1 # Used mainly in the lottery and class change controller
 pillow==6.2.2 # Required for ImageField, which we use in teacher bios
-psycopg2==2.6.1 # Talks to postgres
+psycopg2==2.8.6 # Talks to postgres
 pycurl==7.19.5.1 # Used only in mailing labels and a formstack script which I think is outdated
 pydns==2.3.6 # Used for validating email addresses; imports as "DNS", not "pydns"
 Pygments==2.0.2 # django-extensions dependency