Switch to using CodeCov Action.

Vendor in a cut-down Devel::Cover::Report::Codecov so
that it does not try to upload reports to Codecov.

.github/workflows/coverage.yml

@@ -59,5 +59,10 @@ jobs:
       if: success()
       run: local-coverage/bin/cover --report codecov
       env:
-        PERL5LIB: 'local-coverage/lib/perl5:perllib'
+        PERL5LIB: 'perllib:local-coverage/lib/perl5'
         CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+
+    - uses: codecov/codecov-action@v3
+      if: success()
+      with:
+        files: ./coverage.json

perllib/Devel/Cover/Report/Codecov.pm

@@ -0,0 +1,137 @@
+package Devel::Cover::Report::Codecov;
+use strict;
+use warnings;
+use utf8;
+our $VERSION = '0.25';
+
+use JSON::XS;
+
+sub report {
+    my ($pkg, $db, $options) = @_;
+
+    my $json  = get_codecov_json($options->{file}, $db);
+
+    open(FP, '>coverage.json') or warn $!;
+    print FP $json;
+    close FP;
+}
+
+sub get_file_lines {
+    my ($file) = @_;
+
+    my $lines = 0;
+
+    open my $fp, '<', $file;
+    $lines++ while <$fp>;
+    close $fp;
+
+    return $lines;
+}
+
+sub get_file_coverage {
+    my ($filepath, $db) = @_;
+
+    my $realpath   = get_file_realpath($filepath);
+    my $lines      = get_file_lines($realpath);
+    my $file       = $db->cover->file($filepath);
+    my $statements = $file->statement;
+    my $branches   = $file->branch;
+    my @coverage   = (undef);
+
+    for (my $i = 1; $i <= $lines; $i++) {
+        my $statement = $statements->location($i);
+        my $branch    = defined $branches ? $branches->location($i) : undef;
+        push @coverage, get_line_coverage($statement, $branch);
+    }
+
+    return $realpath => \@coverage;
+}
+
+sub get_line_coverage {
+    my ($statement, $branch) = @_;
+
+    # If all branches covered or uncoverable, report as all covered
+    return $branch->[0]->total.'/'.$branch->[0]->total if $branch && !$branch->[0]->error;
+    return $branch->[0]->covered.'/'.$branch->[0]->total if $branch;
+    return $statement unless $statement;
+    return if $statement->[0]->uncoverable;
+    return $statement->[0]->covered;
+}
+
+sub get_file_realpath {
+    my $file = shift;
+
+    if (-d 'blib') {
+        my $realpath = $file;
+        $realpath =~ s/blib\/lib/lib/;
+
+        return $realpath if -f $realpath;
+    }
+
+    return $file;
+}
+
+sub get_codecov_json {
+    my ($files, $db) = @_;
+
+    my %coverages = map { get_file_coverage($_, $db) } @$files;
+    my $request   = { coverage => \%coverages, messages => {} };
+
+    return encode_json($request);
+}
+
+1;
+__END__
+
+=encoding utf-8
+
+=head1 NAME
+
+Devel::Cover::Report::Codecov - Backend for Codecov reporting of coverage statistics
+
+=head1 SYNOPSIS
+
+    $ cover -report codecov
+
+=head1 DESCRIPTION
+
+Devel::Cover::Report::Codecov is coverage reporter for L<Codecov|https://codecov.io>.
+
+=head1 SEE ALSO
+
+=over 4
+
+=item * L<Devel::Cover>
+
+=back
+
+=head1 LICENSE
+
+The MIT License (MIT)
+
+Copyright (c) 2015-2019 Pine Mizune
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+=head1 AUTHOR
+
+Pine Mizune E<lt>pinemz@gmail.comE<gt>
+
+=cut
+