Does not seem to work when running locally with act

There is a nice tool to run github actions locally: https://github.com/nektos/act

Unfortunately, it seems that it fails on committing `index.yaml` step.

My workflow

```yaml
name: Release Charts

on:
push:
branches:
- master

jobs:
release:
runs-on: ubuntu-latest
permissions:
contents: write
steps:
- name: Checkout
uses: actions/checkout@v2
with:
fetch-depth: 0

- name: Configure Git
run: |
git config user.name "$GITHUB_USER"
git config user.email "$GITHUB_USER@users.noreply.github.com"

- name: Install Helm
uses: azure/setup-helm@v1
with:
version: v3.8.1

- name: Run chart-releaser
uses: helm/chart-releaser-action@v1.4.0
env:
CR_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
with:
charts_dir: helm-charts
```

Run command:
```bash
act --secret-file secret-file -j release --env GITHUB_USER=rafalskolasinski
```
where secret-file contains valid GITHUB_TOKEN.

Logs:

```bash
[Release Charts/release] 🐳 docker exec cmd=[bash --noprofile --norc -e -o pipefail /var/run/act/workflow/4-composite-0.sh] user= workdir=
| Looking up latest tag...
| Discovering changed charts since 'mock-model-0.6.0'...
| Installing chart-releaser on /opt/hostedtoolcache/cr/v1.4.0/x86_64...
| Adding cr directory to PATH...
| Packaging chart 'helm-charts/mock-model'...
| Successfully packaged chart in /home/rskolasinski/work/seldon-models/helm-charts/mock-model and saved it to: .cr-release-packages/mock-model-0.7.0.tgz
| Releasing charts...
| Updating charts repo index...
| ATTENTION: Flag --charts-repo is deprecated. It does not have any effect.
| The index.yaml is read from the 'gh-pages' branch instead.
| Loading index.yaml directly from the charts repository lead to problems as there is a delay between
| pushing to the GitHub pages branch until things appear online.
| The flag will be removed with the next major release.Loading index file from git repository .cr-index/index.yaml
| Preparing worktree (detached HEAD a357179)
| HEAD is now at a357179 Update index.yaml
| Found mock-model-0.7.0.tgz
| Extracting chart metadata from .cr-release-packages/mock-model-0.7.0.tgz
| Calculating Hash for .cr-release-packages/mock-model-0.7.0.tgz
| Updating index .cr-index/index.yaml
| [detached HEAD 8195182] Update index.yaml
| 1 file changed, 11 insertions(+), 1 deletion(-)
| panic: runtime error: index out of range [1] with length 1
|
| goroutine 1 [running]:
| github.com/helm/chart-releaser/pkg/git.(*Git).GetPushURL(0x191a461, {0x19174e9, 0x1e}, {0xc00003e149, 0x28})
| /home/runner/work/chart-releaser/chart-releaser/pkg/git/git.go:80 +0x1df
| github.com/helm/chart-releaser/pkg/releaser.(*Releaser).UpdateIndexFile(0xc000517da8)
| /home/runner/work/chart-releaser/chart-releaser/pkg/releaser/releaser.go:216 +0xb9f
| github.com/helm/chart-releaser/cr/cmd.glob..func1(0x2903a80, {0x191598a, 0x7, 0x7})
| /home/runner/work/chart-releaser/chart-releaser/cr/cmd/index.go:52 +0x1b9
| github.com/spf13/cobra.(*Command).execute(0x2903a80, {0xc00027cd90, 0x7, 0x7})
| /home/runner/go/pkg/mod/github.com/spf13/cobra@v1.4.0/command.go:856 +0x60e
| github.com/spf13/cobra.(*Command).ExecuteC(0x2903f80)
| /home/runner/go/pkg/mod/github.com/spf13/cobra@v1.4.0/command.go:974 +0x3bc
| github.com/spf13/cobra.(*Command).Execute(...)
| /home/runner/go/pkg/mod/github.com/spf13/cobra@v1.4.0/command.go:902
| github.com/helm/chart-releaser/cr/cmd.Execute()
| /home/runner/work/chart-releaser/chart-releaser/cr/cmd/root.go:35 +0x25
| main.main()
| /home/runner/work/chart-releaser/chart-releaser/cr/main.go:20 +0x17
[Release Charts/release] ❌ Failure - owner=$(cut -d '/' -f 1 <<< "$GITHUB_REPOSITORY")
repo=$(cut -d '/' -f 2 <<< "$GITHUB_REPOSITORY")

args=(--owner "$owner" --repo "$repo")
args+=(--charts-dir "${{ inputs.charts_dir }}")

if [[ -n "${{ inputs.version }}" ]]; then
args+=(--version "${{ inputs.version }}")
fi

if [[ -n "${{ inputs.config }}" ]]; then
args+=(--config "${{ inputs.config }}")
fi

if [[ -n "${{ inputs.charts_repo_url }}" ]]; then
args+=(--charts-repo-url "${{ inputs.charts_repo_url }}")
fi

if [[ -z "${{ inputs.install_dir }}" ]]; then
install="$RUNNER_TOOL_CACHE/cr/${{ inputs.version }}/$(uname -m)"
echo "$install" >> "$GITHUB_PATH"
args+=(--install-dir "$install")
else
echo ${{ inputs.install_dir }} >> "$GITHUB_PATH"
args+=(--install-dir "${{ inputs.install_dir }}")
fi

if [[ -n "${{ inputs.install_only }}" ]]; then
args+=(--install-only "${{ inputs.install_only }}")
fi

"$GITHUB_ACTION_PATH/cr.sh" "${args[@]}"
```