Add MSOP-8 EP (mask defined) for MIC5355-S4YMME

Note in datasheet states "as much copper as possible". Therefore very large copper pad with mask at same size as nominal EP.

datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/mic5355_6.pdf#page=15 script: https://github.com/pointhi/kicad-footprint-generator/pull/289 symbol: https://github.com/KiCad/kicad-symbols/pull/1491

MSOP-8-1EP_3x3mm_P0.65mm_Mask1.73x2.36mm:
  size_source: 'http://ww1.microchip.com/downloads/en/DeviceDoc/mic5355_6.pdf#page=15'
  force_small_pitch_ipc_definition: True
  body_size_x:
    nominal: 3
    tolerance: 0.1
  body_size_y:
    nominal: 3.0
    tolerance: 0.1
  body_height:
    nominal: 0.94
    tolerance: 0.1

  overall_size_x:
    nominal: 4.9
    tolerance: 0
  lead_width:
    nominal: 0.33
    tolerance: [-0.1, 0.03]
  lead_len:
    nominal: 0.53
    tolerance: 0.1

  pitch: 0.65
  num_pins_x: 0
  num_pins_y: 4

  EP_size_x:
    nominal: 1.73
    tolerance: 0.15
  EP_size_x_overwrite: 2.5
  EP_mask_x: 1.73
  EP_size_y:
    nominal: 2.36
    tolerance: 0.15
  EP_size_y_overwrite: 3
  EP_mask_y: 2.36
  # EP_paste_coverage: 0.65
  EP_num_paste_pads: [2, 2]

  thermal_vias:
    count: [2, 2]
    drill: 0.2
    # min_annular_ring: 0.15
    paste_via_clearance: 0.1
    EP_num_paste_pads: [2, 2]
    # paste_between_vias: 1
    # paste_rings_outside: 1
    EP_paste_coverage: 0.7
    grid: [1, 1]
    # bottom_pad_size:
    paste_avoid_via: False