Update dependency vuepress to v1.7.1

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
vuepress	devDependencies	minor	1.6.0 -> 1.7.1

---

Release Notes

vuejs/vuepress

### [`v1.7.1`](https://togithub.com/vuejs/vuepress/blob/master/CHANGELOG.md#​171-httpsgithubcomvuejsvuepresscomparev170v171-2020-10-15) [Compare Source](https://togithub.com/vuejs/vuepress/compare/v1.7.0...v1.7.1) ##### Bug Fixes - **$core:** add missing styles for OutboundLink ([#​2662](https://togithub.com/vuejs/vuepress/issues/2662)) ([e2b6641](https://togithub.com/vuejs/vuepress/commit/e2b6641)) - **$core:** reference correct canonical Url frontmatter property (fix [#​2665](https://togithub.com/vuejs/vuepress/issues/2665)) ([fbf5e5d](https://togithub.com/vuejs/vuepress/commit/fbf5e5d)) ### [`v1.7.0`](https://togithub.com/vuejs/vuepress/blob/master/CHANGELOG.md#​170-httpsgithubcomvuejsvuepresscomparev160v170-2020-10-13) [Compare Source](https://togithub.com/vuejs/vuepress/compare/v1.6.0...v1.7.0) ##### Bug Fixes - **$core:** [#​2627](https://togithub.com/vuejs/vuepress/issues/2627) Dup ID violates HTML5-4 ([#​2650](https://togithub.com/vuejs/vuepress/issues/2650)) ([931e7d9](https://togithub.com/vuejs/vuepress/commit/931e7d9)) - adds accessibility to code-group component ([#​2630](https://togithub.com/vuejs/vuepress/issues/2630)) ([35865ec](https://togithub.com/vuejs/vuepress/commit/35865ec)) - scroll hash encoded when non-english chars are used fix [#​2633](https://togithub.com/vuejs/vuepress/issues/2633) ([#​2639](https://togithub.com/vuejs/vuepress/issues/2639)) ([5fcbd88](https://togithub.com/vuejs/vuepress/commit/5fcbd88)) - textlint bug causing PR's to fail checks fix [#​2636](https://togithub.com/vuejs/vuepress/issues/2636) ([#​2637](https://togithub.com/vuejs/vuepress/issues/2637)) ([64e92ca](https://togithub.com/vuejs/vuepress/commit/64e92ca)) ##### Features - **$core:** add canonical link to frontmatter ([#​2658](https://togithub.com/vuejs/vuepress/issues/2658)) ([ff6c51a](https://togithub.com/vuejs/vuepress/commit/ff6c51a))

---

Renovate configuration

:date: Schedule: At any time (no schedule defined).

:vertical_traffic_light: Automerge: Disabled by config. Please merge this manually once you are satisfied.

:recycle: Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

:no_bell: Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box

---

This PR has been generated by WhiteSource Renovate. View repository job log here.