Remove File::Slurp dependency from release scripts

Replace File::Slurp-based version extraction with bash regex
(grep + BASH_REMATCH) in release.sh and ppa-release.sh. Keep
perl -pi -e for portable in-place substitution.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: oschwald

dev-bin/ppa-release.sh

@@ -6,14 +6,12 @@ set -u
 
 DISTS=( groovy focal bionic xenial trusty )
 
-VERSION=$(perl -MFile::Slurp::Tiny=read_file -MDateTime <<EOF
-use v5.16;
-my \$log = read_file(q{Changes.md});
-\$log =~ /^## (\d+\.\d+\.\d+) - (\d{4}-\d{2}-\d{2})/;
-die 'Release time is not today!' unless DateTime->now->ymd eq \$2;
-say \$1;
-EOF
-)
+changelog_header=$(head -n 3 Changes.md)
+if [[ ! $changelog_header =~ ^##\ ([0-9]+\.[0-9]+\.[0-9]+)\ -\ ([0-9]{4}-[0-9]{2}-[0-9]{2}) ]]; then
+    echo "Could not find version in Changes.md!"
+    exit 1
+fi
+VERSION="${BASH_REMATCH[1]}"
 
 RESULTS=/tmp/build-libmaxminddb-results/
 SRCDIR="$RESULTS/libmaxminddb"

dev-bin/release.sh

@@ -81,17 +81,14 @@ if [ -n "$(git status --porcelain)" ]; then
     exit 1
 fi
 
-old_version=$(
-    perl -MFile::Slurp=read_file <<EOF
-use v5.16;
-my \$conf = read_file(q{configure.ac});
-\$conf =~ /AC_INIT.+\[(\d+\.\d+\.\d+)\]/;
-say \$1;
-EOF
-)
+ac_init=$(grep AC_INIT configure.ac)
+if [[ ! $ac_init =~ \[([0-9]+\.[0-9]+\.[0-9]+)\] ]]; then
+    echo "Could not find version in configure.ac!"
+    exit 1
+fi
+old_version="${BASH_REMATCH[1]}"
 
-perl -MFile::Slurp=edit_file -e \
-    "edit_file { s/\Q$old_version/$version/g } \$_ for qw( configure.ac include/maxminddb.h CMakeLists.txt )"
+perl -pi -e "s/\Q$old_version/$version/g" configure.ac include/maxminddb.h CMakeLists.txt
 
 if [ -n "$(git status --porcelain)" ]; then
     git diff