fix(seedsync): nest securityContext values under container (#11092)

**Description**
`ReadOnly Root Filesystem` needs to be disabled by default for
`seedsync` otherwise you won't actually be able to set it up with a
remote server.

You get this with read only, works fine when disabled:
`An error occurred while installing scanner script to remote server:
'Unknown error - mkdir: cannot create directory ‘/home/seedsync’:
Read-only file system /usr/local/bin/run_as_user: 15:
/usr/local/bin/run_as_user: cannot create /var/tmp/passwd: Read-only
file system`

**⚙️ Type of change**

- [ ] ⚙️ Feature/App addition
- [x] 🪛 Bugfix
- [ ] ⚠️ Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] 🔃 Refactor of current code

**🧪 How Has This Been Tested?**

Current version of `seedsync` on stable only works when manually
disabling read-only. I believe it's not pulling the default value due to
a change in structure (missing the nested `container` parent key).

**📃 Notes:**

N/A

**✔️ Checklist:**

- [x] ⚖️ My code follows the style guidelines of this project
- [x] 👀 I have performed a self-review of my own code
- [ ] #️⃣ I have commented my code, particularly in hard-to-understand
areas
- [ ] 📄 I have made corresponding changes to the documentation
- [x] ⚠️ My changes generate no new warnings
- [ ] 🧪 I have added tests to this description that prove my fix is
effective or that my feature works
- [x] ⬆️ I increased versions for any altered app according to semantic
versioning

**➕ App addition**

If this PR is an app addition please make sure you have done the
following.

- [ ] 🪞 I have opened a PR on
[truecharts/containers](https://github.com/truecharts/containers) adding
the container to TrueCharts mirror repo.
- [ ] 🖼️ I have added an icon in the Chart's root directory called
`icon.png`

---

_Please don't blindly check all the boxes. Read them and only check
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charts/stable/seedsync/Chart.yaml

@@ -25,4 +25,4 @@ sources:
   - https://github.com/truecharts/charts/tree/master/charts/stable/seedsync
   - https://github.com/ipsingh06/seedsync
 type: application
-version: 4.0.0
+version: 4.0.1

charts/stable/seedsync/values.yaml

@@ -4,9 +4,10 @@ image:
   tag: latest@sha256:e8e69dcebd7cd9b15af6484736e6d51df49d0e2757e067b1fe8b9b820c6780d1
 
 securityContext:
-  readOnlyRootFilesystem: false
-  runAsGroup: 0
-  runAsUser: 0
+  container:
+    readOnlyRootFilesystem: false
+    runAsGroup: 0
+    runAsUser: 0
 
 service:
   main: