Release commit for dwarf2souces version 0.1.2

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

Update Cargo.toml to bump version to 0.1.2

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

Depending on how a binary is build or post-processes the name attribute
can either be in a supplemental debug file (due to dwz) or be artificial
(due to LTO).

In this cases output warnings, but otherwise process as normal.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>

Allow passing multiple files to determine sources from; The json output
is a dictionary of files to their metadata

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>

Move file processing into its own function; Will make it easier to add
support for multiple files later.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>

Use the anyhow crate for error handler to remove a bunch of boilerplate
as well as better error reporting.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>