dpkg-genbuildinfo: Declare .buildinfo format as stable with version 1.0

All the currently planned changes have been done, let's bump the format
version to denote a stable format, which will not change in incomatible
changes any more without bumping the major version component.

debian/changelog

@@ -2,6 +2,7 @@ dpkg (1.18.23) UNRELEASED; urgency=medium
 
   * Handle unmatched arch-qualified virtual packages in dpkg-genbuildinfo,
     instead of letting perl die. Closes: #849944
+  * Declare .buildinfo format as stable with version 1.0.
   * Documentation:
     - Clarify the requirements for deb-conffile(5) pathnames. Closes: #854417
       Proposed by Dieter Adriaenssens <dieter.adriaenssens@gmail.com>.

man/deb-buildinfo.man

@@ -64,7 +64,7 @@ component.
 Backward incompatible changes to the format will bump the major version,
 and backward compatible changes (such as field additions) will bump the
 minor version.
-The current format version is \fB0.2\fP.
+The current format version is \fB1.0\fP.
 .TP
 .BR Source: " \fIsource-name\fP [\fB(\fP\fIsource-version\fP\fB)\fP] (required)"
 The name of the source package.

scripts/dpkg-genbuildinfo.pl

@@ -64,7 +64,7 @@ my %use_feature = (
     path => 0,
 );
 my @build_profiles = get_build_profiles();
-my $buildinfo_format = '0.2';
+my $buildinfo_format = '1.0';
 my $buildinfo;
 
 my $checksums = Dpkg::Checksums->new();