Compatibility issues with leaflet 1.8

[kancur]

Hi there! It seems that leaflet 1.8 breaks touch zooming functionality.

TANGRAM VERSION: 0.21.1
ENVIRONMENT: Chrome android, Firefox android
TO REPRODUCE THE ISSUE, FOLLOW THESE STEPS:

• try zooming in or out using the touchscreen
  RESULT:
  The map is not being visually updated unless you let off the screen, then it updates to the correct zoom level instantly.
  EXPECTED RESULT:
  You can pinch to zoom in and out

[rwrx]

It is also possible to see this problem on https://trackbook.online

[AMDvsTMD]

relate to Leaflet/Leaflet#8316