Log Message:
textproc/ruby-csv: update to 3.1.7

Update ruby-csv package to 3.1.7.

## 3.1.7 - 2020-08-04

### Improvements

  * Improved document.
    [GitHub#158][GitHub#160][GitHub#161]
    [Patch by Burdette Lamar]

  * Updated required Ruby version to 2.5.0 or later.
    [GitHub#159]
    [Patch by Gabriel Nagy]

  * Removed stringio 0.1.3 or later dependency.

### Thanks

  * Burdette Lamar

  * Gabriel Nagy

## 3.1.6 - 2020-07-20

### Improvements

  * Improved document.
    [GitHub#127][GitHub#135][GitHub#136][GitHub#137][GitHub#139][GitHub#140]
    [GitHub#141][GitHub#142][GitHub#143][GitHub#145][GitHub#146][GitHub#148]
    [GitHub#148][GitHub#151][GitHub#152][GitHub#154][GitHub#155][GitHub#157]
    [Patch by Burdette Lamar]

  * `CSV.open`: Added support for `undef: :replace`.
    [GitHub#129][Patch by Koichi ITO]

  * `CSV.open`: Added support for `invalid: :replace`.
    [GitHub#129][Patch by Koichi ITO]

  * Don't run quotable check for invalid encoding field values.
    [GitHub#131][Patch by Koichi ITO]

  * Added support for specifying the target indexes and names to
    `force_quotes:`.
    [GitHub#153][Reported by Aleksandr]

  * `CSV.generate`: Changed to use the encoding of the first non-ASCII
    field rather than the encoding of ASCII only field.

  * Changed to require the stringio gem 0.1.3 or later.

### Thanks

  * Burdette Lamar

  * Koichi ITO

  * Aleksandr