Fix branchname

[tiborsaas-tw]

Context

We've found an issue with changeset PR-s. The branchname contains a / and file operations in this lib.

Run yarn deploy-docs -b changeset-release/master
yarn run v1.22.18
$ deploy-to-github-pages -d docs-build --verbose -b changeset-release/master
[before-after-hook]: "Hook()" repurposing warning, use "Hook.Collection()". Read more: https://git.io/upgrade-before-after-hook-to-1.4
Error: cp: cannot create directory 'deploy-directory/branch/changeset-release/master': No such file or directory
    at Object.error (/__w/security-web-components/security-web-components/node_modules/shelljs/src/common.js:110:27)
    at /__w/security-web-components/security-web-components/node_modules/shelljs/src/cp.js:2[6](https://github.com/transferwise/security-web-components/actions/runs/4927768868/jobs/8805299272#step:8:7)6:18
    at Array.forEach (<anonymous>)
    at Object._cp (/__w/security-web-components/security-web-components/node_modules/shelljs/src/cp.js:243:11)
    at Object.cp (/__w/security-web-components/security-web-components/node_modules/shelljs/src/common.js:384:25)
    at copyContentWithReplacement (/__w/security-web-components/security-web-components/node_modules/deploy-to-github-pages/lib/deployment/preparation/preparation.js:40:9)
    at prepareDeployDirectory (/__w/security-web-components/security-web-components/node_modules/deploy-to-github-pages/lib/deployment/preparation/preparation.js:16:3)
    at deployToGithubPages (/__w/security-web-components/security-web-components/node_modules/deploy-to-github-pages/lib/deployment/deployment.js:[7](https://github.com/transferwise/security-web-components/actions/runs/4927768868/jobs/8805299272#step:8:8):3)
    at deploy (/__w/security-web-components/security-web-components/node_modules/deploy-to-github-pages/lib/deploy.js:17:[11](https://github.com/transferwise/security-web-components/actions/runs/4927768868/jobs/8805299272#step:8:12))`

Changes

Added a simple replace early on.

Checklist

• I have considered the impact of this change and added a Change Classification Label (change:standard, change:impactful, change:emergency)
• Change meets or does not compromise the Baseline Security Requirements

[oliverviljamaa]

Could've been a patch version as well 👍