CI_SERVER_TLS_CA_FILE generated incorrectly when used on Windows/Powershell executor

Summary

CI_SERVER_TLS_CA_FILE generated incorrectly when used on Windows/Powershell

Steps to reproduce

git config: http.sslBackend = openssl

config.toml: [runners] tls-ca-file = "tls-ca-file.pem"

Actual behavior

fatal: unable to access 'https://xxxxx/xxx.git/': SSL certificate problem: unable to get issuer certificate

Expected behavior

cert. ok

Environment description

$PSVersionTable
Name                           Value
----                           -----
PSVersion                      5.1.17134.858
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.17134.858
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Used GitLab Runner version

.\gitlab-runner.exe --version
Version:      12.4.0
Git revision: 1564076b
Git branch:   12-4-stable
GO version:   go1.10.8
Built:        2019-10-21T14:37:13+0000
OS/Arch:      windows/amd64

Possible fixes

CI_SERVER_TLS_CA_FILE generated in UTF-8 Encoding with BOM, so

- $CI_SERVER_TLS_CA_FILE | Out-File "C:\GitLab-Runner\builds\0\project-1.tmp\CI_SERVER_TLS_CA_FILE"
+ $CI_SERVER_TLS_CA_FILE | Out-File "C:\GitLab-Runner\builds\0\project-1.tmp\CI_SERVER_TLS_CA_FILE" -Encoding ascii