Pin SQLAlchemy<2 for sunpy

Author: pllim

tox.ini

@@ -12,6 +12,7 @@ envlist =
 requires =
     setuptools >= 30.3.0
     pip >= 19.3.1
+    tox < 4
 isolated_build = true
 
 [testenv]
@@ -33,6 +34,7 @@ deps =
     reproject,all: git+https://github.com/astropy/reproject.git#egg=reproject[test,all]
     specreduce,all: git+https://github.com/astropy/specreduce.git#egg=specreduce[test]
     specutils,all: git+https://github.com/astropy/specutils.git#egg=specutils[all,test]
+    sunpy,all: SQLAlchemy<2
     sunpy,all: git+https://github.com/sunpy/sunpy.git#egg=sunpy[tests,all]
 
 skip_install = true