Description of proposed changes

• sensor:

  • add seasat PRF
  • add NISAR range_pixel_size

• ERA5: consistent naming with better error msg

  • use ERA5 throughout mintpy without a hyphen, to avoid confusion.
  • smallbaselineApp.py: raise error for un-recognized GAM names

• timeseries_rms: simplify the plot

• utils/plot: omit "Time [year]" x-axis label to save space as it's not informative

• prep_snap: typo fix

Reminders

• Pass Codacy code review (green)
• Pass Circle CI / local test (green)
• Make sure that your code follows our style. Use the other functions/files as a basis.
• If modifying functionality, describe changes to function behavior and arguments in a comment below the function declaration.