Onyxia fails to parse some manifests

Since the latest dependencies bump it seems Onyxia fails to parse some manifests.
I'm trying to reproduce
```
2023-06-19 08:48:26.661 ERROR 7 --- [nio-8080-exec-7] o.a.c.c.C.[.[.[.[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [/api] threw exception [Request processing failed; nested exception is java.util.concurrent.ExecutionException: while scanning a block scalar
in reader, line 150, column 26:
pre-entrypoint-script: |
^
the leading empty lines contain more spaces (3) than the first non-empty line.
in reader, line 151, column 1:
---
^
] with root cause

org.snakeyaml.engine.v2.exceptions.ScannerException: while scanning a block scalar
in reader, line 150, column 26:
pre-entrypoint-script: |
^
the leading empty lines contain more spaces (3) than the first non-empty line.
in reader, line 151, column 1:
---
^

at org.snakeyaml.engine.v2.scanner.ScannerImpl.scanBlockScalar(ScannerImpl.java:1546) ~[snakeyaml-engine-2.6.
```