Bump apigee-client-php version requirement to 2.1.0 for AppGroup

[shishir-intelli]

Support for AppGroup/ Apigee X Teams.

[divya-intelli]

LGTM

[codecov]

Codecov Report

Merging #875 (1ffdae6) into 2.x (386c83f) will decrease coverage by 0.95%.
The diff coverage is 23.25%.

@@             Coverage Diff              @@
##                2.x     #875      +/-   ##
============================================
- Coverage     44.89%   43.94%   -0.95%     
- Complexity     2903     3019     +116     
============================================
  Files           337      342       +5     
  Lines         10748    11102     +354     
============================================
+ Hits           4825     4879      +54     
- Misses         5923     6223     +300     

Impacted Files	Coverage Δ
.../apigee_edge_actions/src/TeamMembershipManager.php	81.25% <0.00%> (-5.42%)	⬇️
..._edge_teams/src/Access/ManageTeamMembersAccess.php	20.00% <0.00%> (ø)
...pigee_edge_teams/src/AppGroupMembersController.php	0.00% <0.00%> (ø)
...apigee_edge_teams/src/CompanyMembersController.php	90.47% <ø> (ø)
...igee_edge_teams/src/Controller/TeamMembersList.php	0.00% <0.00%> (ø)
...les/apigee_edge_teams/src/Entity/AppGroupCache.php	0.00% <0.00%> (ø)
...Controller/TeamAppApigeeXEntityControllerProxy.php	0.00% <0.00%> (ø)
...ee_edge_teams/src/Entity/Form/TeamAppFormTrait.php	0.00% <0.00%> (ø)
...les/apigee_edge_teams/src/Entity/Form/TeamForm.php	0.00% <0.00%> (ø)
...apigee_edge_teams/src/Entity/TeamAccessHandler.php	0.00% <0.00%> (ø)
... and 26 more