software/slapos-sr-testing: install new psycopg2 dependency

This is a dependency of slapos.cookbook[test] since 90650d2c (
recipe/test_postgres: test with a real postgres server, 2021-11-12) and
because we run software schema tests from slapos.cookbook in
software/slapos-sr-testing, we also need the dependency here.

software/slapos-sr-testing/software.cfg

@@ -8,6 +8,7 @@ extends =
   ../../component/pycurl/buildout.cfg
   ../../component/faketime/buildout.cfg
   ../../component/pillow/buildout.cfg
+  ../../component/psycopg2/buildout.cfg
   ../../component/python-cryptography/buildout.cfg
   ../../component/python-mysqlclient/buildout.cfg
   ../../component/python-pynacl/buildout.cfg
@@ -242,6 +243,7 @@ extra-eggs =
   ${python-mysqlclient:egg}
   ${backports.lzma:egg}
   ${bcrypt:egg}
+  ${psycopg2:egg}
   slapos.libnetworkcache
   supervisor
   ${slapos.cookbook-setup:egg}
@@ -393,3 +395,4 @@ mysqlclient = 1.3.12
 pexpect = 4.8.0
 ptyprocess = 0.6.0
 typing = 3.7.4.3
+psycopg2 = 2.8.6