Refactor install.sh (#765)

* [wip] get assets based on gh api

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* put install.sh download_asset fn under test

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* put install.sh install_asset fn under test

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* use zip for darwin installs

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* fix install.sh negative test cases

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* allow errors to propagate in install.sh

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* remove exit on error from install.sh tests

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* add more docs around install.sh helpers

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* add integration tests for install.sh

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* add install.sh testing to pipeline

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* add install test cache to CI

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* make colors globally available

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* test download against github release

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* always test release-based install against latest release

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* use better install.sh test names

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

syft/pkg/cataloger/java/test-fixtures/java-builds/Makefile

@@ -65,5 +65,5 @@ clean-jenkins:
 # we need a way to determine if CI should bust the test cache based on the source material
 $(PKGSDIR).fingerprint: clean-examples
 	mkdir -p $(PKGSDIR)
-	find example-* -type f -exec sha256sum {} \; | sort | tee $(PKGSDIR).fingerprint
+	find example-* -type f -exec sha256sum {} \; | sort | tee /dev/stderr | tee $(PKGSDIR).fingerprint
 	sha256sum $(PKGSDIR).fingerprint