Update reqwest requirement from 0.11 to 0.12 #15

Job	Run time
Clippy	3m 58s
semver	39s
Rustfmt	14s
Tests (ubuntu-latest, firefox, plotly_ndarray,plotly_image,static_export_geckodriver,static_expor...	3m 4s
Tests (windows-latest, chrome, plotly_ndarray,plotly_image,static_export_chromedriver,debug)	6m 17s
Tests (ubuntu-latest, chrome, plotly_ndarray,plotly_image,static_export_default,debug)	3m 15s
Build Wasm Examples (callback-example)	55s
Build Wasm Examples (basic)	55s
Code Coverage	21s
Tests (macos-latest, chrome, plotly_ndarray,plotly_image,static_export_default,debug)	4m 6s
Build Book	3m 47s
Build Examples (3d_charts)	34s
Build Examples (customization/density_mapbox_example)	26s
Build Examples (basic_charts)	34s
Build Examples (images)	51s
Build Examples (customization/consistent_static_format_export)	1m 25s
Build Examples (ndarray)	35s
Build Examples (financial_charts)	31s
Build Examples (kaleido)	1m 45s
Build Examples (subplots)	31s
Build Examples (themes)	35s
Build Examples (custom_controls)	36s
Build Examples (statistical_charts)	25s
Build Examples (scientific_charts)	31s
Build Examples (maps)	36s
Build Examples (shapes)	28s
Build Examples (customization/multiple_plots_example)	32s
	38m 26s

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