Upgrade to tm version 23.0. (#1927)

* Start upgrade. Currently go test ./... hangs.

* (squash this) Fix staking tests

* wip

* note what changes need to be made to make this work on tm v0.23.0

* Fix addr -> pubkey map

* cleanup code

* Fix slashing test failures except for begin blocker

* fix all slashing tests

* fix lcd tests

* Address PR comments

* add link to changelog.

* (wip) start making addrToPubkey map persisted. Since amino can't handle maps,
we have to change from what this commit is doing.

* Use the correct method of storing a map

* (squash this) address PR comments

* Did you run 'make'?

* remove gaiadebug binary

docs/sdk/core/app2.md

@@ -150,7 +150,7 @@ func NewCodec() *wire.Codec {
 ```
 
 Note: We also register the types in the `tendermint/tendermint/crypto` module so that `crypto.PubKey`
-and `crypto.Signature` are encoded/decoded correctly.
+is encoded/decoded correctly.
 
 Amino supports encoding and decoding in both a binary and JSON format.
 See the [codec API docs](https://godoc.org/github.com/tendermint/go-amino#Codec) for more details.
@@ -166,7 +166,7 @@ type app2Tx struct {
     sdk.Msg
     
     PubKey    crypto.PubKey
-    Signature crypto.Signature
+    Signature []byte
 }
 
 // This tx only has one Msg.

docs/sdk/core/app3.md

@@ -160,7 +160,7 @@ The standard form for signatures is `StdSignature`:
 // the first transaction made by the account.
 type StdSignature struct {
 	crypto.PubKey    `json:"pub_key"` // optional
-	crypto.Signature `json:"signature"`
+	[]byte `json:"signature"`
 	AccountNumber    int64 `json:"account_number"`
 	Sequence         int64 `json:"sequence"`
 }

docs/sdk/core/examples/app2.go

@@ -183,7 +183,7 @@ type app2Tx struct {
 	sdk.Msg
 
 	PubKey    crypto.PubKey
-	Signature crypto.Signature
+	Signature []byte
 }
 
 // This tx only has one Msg.
@@ -191,7 +191,7 @@ func (tx app2Tx) GetMsgs() []sdk.Msg {
 	return []sdk.Msg{tx.Msg}
 }
 
-func (tx app2Tx) GetSignature() crypto.Signature {
+func (tx app2Tx) GetSignature() []byte {
 	return tx.Signature
 }