update req for downloading from b2share

requirements.txt

@@ -37,7 +37,7 @@ pydot==1.4.1
 pyparsing==2.4.6
 pyproj==2.5.0
 pyshp==2.1.0
-pytest==6.0.0
+pytest~=5.3.5
 pytest-cov==2.10.0
 pytest-html==2.1.1
 pytest-lazy-fixture==0.6.3
@@ -61,9 +61,11 @@ typing-extensions
 urllib3==1.25.8
 wcwidth==0.1.8
 Werkzeug==1.0.0
-xarray==0.16.1
+xarray~=0.15.0
 zipp==3.1.0
 
 setuptools~=49.6.0
 Cartopy==0.18.0
---no-binary shapely Shapely==1.7.0
+--no-binary shapely Shapely==1.7.0
\ No newline at end of file
+mlair~=0.12.1
+wget~=3.2
\ No newline at end of file