Update reqwest requirement from 0.11 to 0.12 #20

Job	Run time
semver	46s
Rustfmt	14s
Clippy	4m 0s
Code Coverage	21s
Tests (ubuntu-latest, firefox, plotly_ndarray,plotly_image,static_export_geckodriver,static_expor...	3m 19s
Tests (macos-latest, chrome, plotly_ndarray,plotly_image,static_export_default,debug)	2m 47s
Build Book	3m 22s
Tests (ubuntu-latest, chrome, plotly_ndarray,plotly_image,static_export_default,debug)	3m 8s
Tests (windows-latest, chrome, plotly_ndarray,plotly_image,static_export_chromedriver,debug)	5m 23s
Build Wasm Examples (callback-example)	59s
Build Wasm Examples (basic)	59s
Build Examples (3d_charts)	34s
Build Examples (basic_charts)	36s
Build Examples (customization/consistent_static_format_export)	1m 29s
Build Examples (custom_controls)	40s
Build Examples (customization/density_mapbox_example)	29s
Build Examples (ndarray)	34s
Build Examples (images)	49s
Build Examples (customization/multiple_plots_example)	34s
Build Examples (maps)	45s
Build Examples (financial_charts)	34s
Build Examples (shapes)	30s
Build Examples (kaleido)	1m 20s
Build Examples (themes)	38s
Build Examples (statistical_charts)	31s
Build Examples (subplots)	33s
Build Examples (scientific_charts)	31s
	36m 25s

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