bubblewrap update with --manifest: ERROR ENOENT: no such file or directory, open 'https:/...'

**Describe the bug**

```
bubblewrap update --manifest https://kleinanzeigen.goeppingen.social/manifest.webmanifest
cli ERROR ENOENT: no such file or directory, open 'https://kleinanzeigen.goeppingen.social/manifest.webmanifest'
```

**To Reproduce**
Steps to reproduce the behavior:
1. bubblewrap init --manifest https://kleinanzeigen.goeppingen.social/manifest.webmanifest
2. bubblewrap update --manifest https://kleinanzeigen.goeppingen.social/manifest.webmanifest
3. See error

**Expected behavior**
As with init, update should get the manifest from the remote https url.

**Screenshots**
N/A

**Desktop (please complete the following information):**
- OS: archlinux
- Browser irrelevant
- Version n/a

**Smartphone (please complete the following information):**
- Device: n/a
- OS: n/a
- Browser n/a
- Version n/a

**Additional context**
`curl https://kleinanzeigen.goeppingen.social/manifest.webmanifest`
```json
{"name":"Kleinanzeigen Kreis Göppingen","short_name":"GP Anzeigen","start_url":"/","display":"standalone","background_color":"#111827","lang":"de","scope":"/","description":"Kostenlose Kleinanzeigen für den Kreis Göppingen. Mit dieser App können private und/oder gewerbliche Nutzer kostenlos Kleinanzeigen aufgeben und lesen, allerdings nur für Angebote im Kreis Göppingen.","orientation":"portrait","theme_color":"#1F2937","icons":[{"src":"icons/icon-128x128.png","sizes":"128x128","type":"image/png"},{"src":"icons/icon-192x192.png","sizes":"192x192","type":"image/png"},{"src":"icons/icon-256x256.png","sizes":"256x256","type":"image/png"},{"src":"icons/icon-384x384.png","sizes":"384x384","type":"image/png"},{"src":"icons/icon-512x512.png","sizes":"512x512","type":"image/png"}]}
```

```
bubblewrap --version
,-----. ,--. ,--. ,--.
| |) /_,--.,--| |-.| |-.| |,---.,--. ,--,--.--.,--,--.,---.
| .-. | || | .-. | .-. | | .-. | |.'.| | .--' ,-. | .-. |
| '--' ' '' | `-' | `-' | \ --| .'. | | \ '-' | '-' '
`------' `----' `---' `---'`--'`----'--' '--`--' `--`--| |-'
`--'
(node:91850) [DEP0040] DeprecationWarning: The `punycode` module is deprecated. Please use a userland alternative instead.
(Use `node --trace-deprecation ...` to show where the warning was created)
version 1.22.0
```