fix(deps): update pdf-extract 0.7 -> 0.8 to fix PDF parsing crashes (#4)

[andrehrferreira]

Description

Certain PDF files caused the application to crash during parsing with pdf-extract 0.7.x. This bumps pdf-extract to 0.8 (resolves to 0.8.2), which fixes the upstream parsing bugs. The extraction API (extract_text, extract_text_from_mem) is unchanged, so no source changes were needed. Also bumps the crate version to 0.3.3 and updates the CHANGELOG.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Performance improvement
• Code refactoring

Related Issue

Fixes #4

Changes Made

• Updated pdf-extract dependency from 0.7 to 0.8 (resolves to 0.8.2) in Cargo.toml
• Bumped crate version from 0.3.2 to 0.3.3
• Added a 0.3.3 bugfix entry to CHANGELOG.md

Testing

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed
• Benchmarks run (if performance-related)

Verified locally:

• cargo build succeeds with pdf-extract 0.8.2 — no API changes required.
• Full test suite passes (88 passed; 0 failed).
• Manually re-ran the test_pdf_extract example against data/1706.03762v7.pdf; the PDF parses and extracts text without crashing.

Checklist

• My code follows the project's style guidelines
• 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
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published

Performance Impact

• Conversion speed: No measurable change (dependency-only update)
• Memory usage: No measurable change
• Binary size: Negligible change

Additional Notes

This is a dependency-only fix — no source code changes. pdf-extract 0.10.0 is also available, but this PR stays within the requested 0.8.x line for a minimal, low-risk update. Note: the extraction example still prints upstream Unicode mismatch / missing char warnings from pdf-extract, which are non-fatal and unrelated to the crash.