Bug: OAuth1 signature fails with array parameters due to double encoding

[Bikash-bluebash]

Description

When using array parameters like 'includes[]': %w[value1 value2] in requests, the OAuth1 signature calculation fails with a 401 unauthorized error. This happens because the square brackets ([]) are being double-encoded in the signature base string.

Problem Details

The signature base string was incorrectly encoding includes[] as includes%255B%255D instead of the correct includes%5B%5D. This double encoding (%25 is the encoding for %) causes the server to reject the signature.

Steps to Reproduce

1. Make a request with parameters including an array:

request(:get, 'example/endpoint',
  params: {
    param1: 'value1',
    'includes[]': %w[value1 value2]
  }
)