bump sqlalchemy and sqlalchemy-utils; update .travis.yml

[vpsx]

tldr: bump sqlalchemy and sqlalchemy-utils. Also specify jdk 8 in .travis.yml.

Tried to just bump sqlalchemy and sqlalchemy-utils. Travis error:

Package oracle-java8-set-default is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
  oracle-java9-set-default

Probably because: https://launchpad.net/~webupd8team/+archive/ubuntu/java

The Travis dist was trusty (just because that is the default)(...until tomorrow!). Switching from java8 to java9 worked, as did doing

before_install:
  - jdk_switcher use oraclejdk8

in trusty. But we prefer xenial(and it's the new default), and we don't really care about jdk 8 or 9 so long as Swagger works, so settled on specifying

dist: xenial
jdk: 
    - oraclejdk8

Dependency updates

bump sqlalchemy from 1.0.8 to 1.3.3
bump sqlalchemy-utils from 0.32.21 to 0.33.11

[fantix]

Sorry to comment on a closed PR: you probably need to update the versions in setup.py too.