placekey_id for Visits data

Hello! A quick note for other Visits users: preview_dewey_duck() doesn't register a placekey column, but there is one in the data. You'll get it if you call the API without a select clause or (presumably) if you include placekey in your select clause.

# No placekey in preview
> print(colnames(preview_dewey_duck(api_key, visits, limit = 0)))
 [1] "utc_timestamp"      "local_timestamp"    "caid"               "id_type"            "location_name"     
 [6] "top_category"       "sub_category"       "street_address"     "city"               "state"             
[11] "naics_code"         "brands"             "zip_code"           "minimum_dwell"      "safegraph_place_id"
[16] "geohash_5"          "census_block_group"

# BUT placekey present in data
> names(dat)
 [1] "utc_timestamp"      "local_timestamp"    "id_type"            "caid"               "location_name"     
 [6] "top_category"       "sub_category"       "street_address"     "city"               "state"             
[11] "zipcode"            "geohash_5"          "census_block_group" "naics_code"         "brands"            
[16] "minimum_dwell"      "safegraph_place_id" "placekey"