iox-#70 Fix clippy warnings

[elBoberido]

Pre-Review Checklist for the PR Author

1. [x] Code follows the Rust coding style and is formatted with rustfmt
2. [x] Branch follows the naming format (iox-123-this-is-a-branch)
3. [x] Commits messages are according to this guideline
   • [x] Commit messages have the issue ID (iox-#42 commit text)
   • [x] Commit author matches Eclipse Contributor Agreement (and ECA is signed)
4. [x] Update the PR title
   • Follow the same conventions as for commit messages
   • Link to the relevant issue
5. [x] Relevant issues are linked
6. [x] Add sensible notes for the reviewer
7. [x] All checks have passed (except task-list-completed)
8. [x] Assign PR to reviewer

Notes for Reviewer

This PR fixes all the clippy warnings.

Checklist for the PR Reviewer

• [ ] Commits are properly organized and messages are according to the guideline
• [ ] Code according to our coding style and naming conventions
• [ ] PR title describes the changes

Post-review Checklist for the PR Author

1. [ ] All open points are addressed and tracked via issues

References

• Closes #70

[codecov-commenter]

Codecov Report

Merging #71 (55d6aee) into master (f7573d8) will decrease coverage by 0.95%. The diff coverage is 35.24%.

@@            Coverage Diff             @@
##           master      #71      +/-   ##
==========================================
- Coverage   50.77%   49.83%   -0.95%     
==========================================
  Files          20       20              
  Lines        1154     1202      +48     
==========================================
+ Hits          586      599      +13     
- Misses        568      603      +35     

Files Changed	Coverage Δ
iceoryx-sys/src/introspection/memory.rs	0.00% <0.00%> (ø)
iceoryx-sys/src/introspection/port.rs	0.00% <0.00%> (ø)
iceoryx-sys/src/introspection/process.rs	0.00% <0.00%> (ø)
iceoryx-sys/src/sample.rs	53.24% <ø> (ø)
iceoryx-sys/src/publisher.rs	81.67% <57.69%> (-1.39%)	:arrow_down:
iceoryx-sys/src/subscriber.rs	72.91% <59.45%> (-0.98%)	:arrow_down:
iceoryx-sys/src/chunk_header.rs	100.00% <100.00%> (ø)