Release coq-rewriter 0.0.12

```bash

pkg="$1"
oldver="$2"
newver="$3"

function usage() {
    printf "USAGE: %s PKG OLDVER NEWVER\n" "$0"
}

if [ -z "$pkg" ] || [ -z "$oldver" ] || [ -z "$newver" ]; then
    usage;
    exit 1;
fi

set -ex

cd "$(git rev-parse --show-toplevel)"
pwd
pushd "released/packages/coq-${pkg}"
oldopam="coq-${pkg}.${oldver}/opam"
newopam="coq-${pkg}.${newver}/opam"
mkdir -p "coq-${pkg}.${newver}"
cp -f "$oldopam" "$newopam"
git add "$newopam"
sed -i "s/${oldver}/${newver}/g" "$newopam"
url="$(grep -o '^\s*src: .*' "$newopam" | grep -o '"[^"]*"' | tr -d '"')"
wget "$url" -O "$newver.tar.gz"
sha512="$(sha512sum "$newver.tar.gz" | cut -d' ' -f1)"
sed -i 's/\(checksum:[^"]*"\)[^"]*\("\)/\1sha512='"${sha512}"'\2/g' "$newopam"
git diff "$newopam"
git add "$newopam"
```

```
./release-next.sh rewriter 0.0.11 0.0.12
```

released/packages/coq-rewriter/coq-rewriter.0.0.12/opam

@@ -0,0 +1,25 @@
+opam-version: "2.0"
+authors: [
+  "Google Inc."
+  "Massachusetts Institute of Technology"
+]
+maintainer: "Jason Gross <jgross@mit.edu>"
+homepage: "https://github.com/mit-plv/rewriter"
+bug-reports: "https://github.com/mit-plv/rewriter/issues"
+license: "MIT OR Apache-2.0 OR BSD-1-Clause"
+build: [
+  [make "-j%{jobs}%"]
+]
+install: [make "install"]
+depends: [
+  "conf-findutils" {build}
+  "ocaml" {build & (arch = "x86_32" | arch = "x86_64" | >= "4.14.0")}
+  "coq" {>= "8.18~"}
+]
+dev-repo: "git+https://github.com/mit-plv/rewriter.git"
+synopsis: "Reflective PHOAS rewriting/pattern-matching-compilation framework for simply-typed equalities and let-lifting, experimental and tailored for use in Fiat Cryptography"
+tags: ["logpath:Rewriter"]
+url {
+  src: "https://github.com/mit-plv/rewriter/archive/refs/tags/v0.0.12.tar.gz"
+  checksum: "sha512=e0c45d39c0d28cd786290292b70d788ab9e6327a4afe9c37e4427dc97f9c6a0d00b0865da25ae2624d7c0f4f339754962bded3a478576e6f6896bbf31904689e"
+}