Make gemspecs reproducible

Without an explicit date, they will get the current date and make the
build unreproducible

Gbp-Pq: Name Make-gemspecs-reproducible.patch

Author: terceiro

.bundle/gems/bigdecimal-3.1.8/bigdecimal.gemspec

@@ -14,6 +14,7 @@ Gem::Specification.new do |s|
   s.name          = name
   s.version       = source_version
   s.authors       = ["Kenta Murata", "Zachary Scott", "Shigeo Kobayashi"]
+  s.date          = RUBY_RELEASE_DATE
   s.email         = ["mrkn@mrkn.jp"]
 
   s.summary       = "Arbitrary-precision decimal floating-point number library."

ext/fiddle/fiddle.gemspec

@@ -8,6 +8,7 @@ end
 Gem::Specification.new do |spec|
   spec.name          = "fiddle"
   spec.version       = version_module::Fiddle::VERSION
+  spec.date          = RUBY_RELEASE_DATE
   spec.authors       = ["Aaron Patterson", "SHIBATA Hiroshi"]
   spec.email         = ["aaron@tenderlovemaking.com", "hsbt@ruby-lang.org"]
 

ext/io/console/io-console.gemspec

@@ -12,6 +12,7 @@ end
 Gem::Specification.new do |s|
   s.name = "io-console"
   s.version = _VERSION
+  s.date = RUBY_RELEASE_DATE
   s.summary = "Console interface"
   s.email = "nobu@ruby-lang.org"
   s.description = "add console capabilities to IO instances."

lib/ipaddr.gemspec

@@ -18,6 +18,7 @@ end
 Gem::Specification.new do |spec|
   spec.name          = "ipaddr"
   spec.version       = version
+  spec.date          = RUBY_RELEASE_DATE
   spec.authors       = ["Akinori MUSHA", "Hajimu UMEMOTO"]
   spec.email         = ["knu@idaemons.org", "ume@mahoroba.org"]
 

lib/rdoc/rdoc.gemspec

@@ -7,6 +7,7 @@ end
 
 Gem::Specification.new do |s|
   s.name = "rdoc"
+  s.date = RUBY_RELEASE_DATE
   s.version = RDoc::VERSION
 
   s.authors = [