build: bump dependencies in .kokoro/requirements.txt

[dependabot]

Bumps urllib3 from 1.26.12 to 1.26.18.

Release notes

Sourced from urllib3's releases.

1.26.18

• Made body stripped from HTTP requests changing the request method to GET after HTTP 303 "See Other" redirect responses. (GHSA-g4mx-q9vg-27p4)

1.26.17

• Added the Cookie header to the list of headers to strip from requests when redirecting to a different host. As before, different headers can be set via Retry.remove_headers_on_redirect. (GHSA-v845-jxx5-vc9f)

1.26.16

• Fixed thread-safety issue where accessing a PoolManager with many distinct origins would cause connection pools to be closed while requests are in progress (#2954)

1.26.15

• Fix socket timeout value when HTTPConnection is reused (urllib3/urllib3#2645)
• Remove "!" character from the unreserved characters in IPv6 Zone ID parsing (urllib3/urllib3#2899)
• Fix IDNA handling of 'x80' byte (urllib3/urllib3#2901)

1.26.14

• Fixed parsing of port 0 (zero) returning None, instead of 0 (#2850)
• Removed deprecated HTTPResponse.getheaders() calls in urllib3.contrib module.

1.26.13

• Deprecated the HTTPResponse.getheaders() and HTTPResponse.getheader() methods.
• Fixed an issue where parsing a URL with leading zeroes in the port would be rejected even when the port number after removing the zeroes was valid.
• Fixed a deprecation warning when using cryptography v39.0.0.
• Removed the <4 in the Requires-Python packaging metadata field.

Changelog

Sourced from urllib3's changelog.

1.26.18 (2023-10-17)

• Made body stripped from HTTP requests changing the request method to GET after HTTP 303 "See Other" redirect responses.

1.26.17 (2023-10-02)

• Added the Cookie header to the list of headers to strip from requests when redirecting to a different host. As before, different headers can be set via Retry.remove_headers_on_redirect. ([#3139](https://github.com/urllib3/urllib3/issues/3139) <https://github.com/urllib3/urllib3/pull/3139>_)

1.26.16 (2023-05-23)

• Fixed thread-safety issue where accessing a PoolManager with many distinct origins would cause connection pools to be closed while requests are in progress ([#2954](https://github.com/urllib3/urllib3/issues/2954) <https://github.com/urllib3/urllib3/pull/2954>_)

1.26.15 (2023-03-10)

• Fix socket timeout value when HTTPConnection is reused ([#2645](https://github.com/urllib3/urllib3/issues/2645) <https://github.com/urllib3/urllib3/issues/2645>__)
• Remove "!" character from the unreserved characters in IPv6 Zone ID parsing ([#2899](https://github.com/urllib3/urllib3/issues/2899) <https://github.com/urllib3/urllib3/issues/2899>__)
• Fix IDNA handling of '\x80' byte ([#2901](https://github.com/urllib3/urllib3/issues/2901) <https://github.com/urllib3/urllib3/issues/2901>__)

1.26.14 (2023-01-11)

• Fixed parsing of port 0 (zero) returning None, instead of 0. ([#2850](https://github.com/urllib3/urllib3/issues/2850) <https://github.com/urllib3/urllib3/issues/2850>__)
• Removed deprecated getheaders() calls in contrib module. Fixed the type hint of PoolKey.key_retries by adding bool to the union. ([#2865](https://github.com/urllib3/urllib3/issues/2865) <https://github.com/urllib3/urllib3/issues/2865>__)

1.26.13 (2022-11-23)

• Deprecated the HTTPResponse.getheaders() and HTTPResponse.getheader() methods.
• Fixed an issue where parsing a URL with leading zeroes in the port would be rejected even when the port number after removing the zeroes was valid.
• Fixed a deprecation warning when using cryptography v39.0.0.
• Removed the <4 in the Requires-Python packaging metadata field.

Commits

• 9c2c230 Release 1.26.18 (#3159)
• b594c5c Merge pull request from GHSA-g4mx-q9vg-27p4
• 944f0eb [1.26] Use vendored six in urllib3.contrib.securetransport
• c9016bf Release 1.26.17
• 0122035 Backport GHSA-v845-jxx5-vc9f (#3139)
• e63989f Fix installing brotli extra on Python 2.7
• 2e7a24d [1.26] Configure OS for RTD to fix building docs
• 57181d6 [1.26] Improve error message when calling urllib3.request() (#3058)
• 3c01480 [1.26] Run coverage even with failed jobs
• d94029b Release 1.26.16
• Additional commits viewable in compare view

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[dependabot]

Superseded by #3961.