Fix compilation warnings

[dkovba]

Fix compilation warnings:

.../Sources/Containerization/LinuxContainer.swift:877:35: warning: 'weak' ownership of capture 'self' differs from implicitly-captured strong reference in outer scope [#ImplicitStrongCapture]
851 | /// via the `start` method.
852 | public func exec(_ id: String, configuration: @Sendable @escaping (inout LinuxProcessConfiguration) throws -> Void) async throws -> LinuxProcess {
853 | try await self.state.withLock { state in
| |- note: 'self' implicitly strongly captured here
| `- note: add 'self' as a capture list item to silence
854 | var startedState = try state.startedState("exec")
855 | :
875 | vm: startedState.vm,
876 | logger: self.logger,
877 | onDelete: { [weak self] in
| |- warning: 'weak' ownership of capture 'self' differs from implicitly-captured strong reference in outer scope [#ImplicitStrongCapture]
| `- note: explicitly assign the capture list item to silence
878 | await self?.removeProcess(id: id)
879 | }
.../Sources/Containerization/LinuxContainer.swift:914:35: warning: 'weak' ownership of capture 'self' differs from implicitly-captured strong reference in outer scope [#ImplicitStrongCapture]
890 | /// via the `start` method.
891 | public func exec(_ id: String, configuration: LinuxProcessConfiguration) async throws -> LinuxProcess {
892 | try await self.state.withLock {
| |- note: 'self' implicitly strongly captured here
| `- note: add 'self' as a capture list item to silence
893 | var state = try $0.startedState("exec")
894 | :
912 | vm: state.vm,
913 | logger: self.logger,
914 | onDelete: { [weak self] in
| |- warning: 'weak' ownership of capture 'self' differs from implicitly-captured strong reference in outer scope [#ImplicitStrongCapture]
| `- note: explicitly assign the capture list item to silence
915 | await self?.removeProcess(id: id)
916 | }
[#ImplicitStrongCapture]: <https://docs.swift.org/compiler/documentation/diagnostics/implicit-strong-capture>